Well there are 4 components of the Big Bang theory:
The first is that the universe is constantly expanding. When the Big Bang happened it started as a small, condensed, ball of Hydrogen that was smaller than a pinhead. This means that when it exploded it started expanding rapidly. In 1912, Slipher figured out that everything was moving away from us by measuring distances, but he thought it was all in the Milky Way Galaxy. In 1942, however, Hubble figured out that it wasn’t just the Milky Way Galaxy. He figured out that everything in the UNIVERSE was moving away, not just things in the Milky Way Galaxy. This started more interest in the theory. They found out that nothing was more than 13. 8 billion years old, therefore making the whole universe 13.8 billion years old. This made everyone realize that the whole universe started 13.8 billion years ago, or the Big Bang.
The second is that all of the elements in the universe are in the same ratio everywhere. What this means is that in every single point in the universe has the same exact amount of elements, which are Hydrogen and Helium. Due to this, scientists believe that the tiny ball, smaller than a pinhead, was heavily compressed star that exploded. This star was no ordinary star. This was more heavily compacted than any black hole there is. There was no other elements besides Hydrogen. So, when the “star” exploded the heat and pressure of the explosion was enough to create a universe after it cooled down.
The third is that the Big Bang created cosmic radiation. Light is a wave. For the light to change to microwaves it needed a catalyst which was the explosion. When it exploded the light waves expanded so much they became a new type of wave, a microwave. Think about it like this. Imagine you have a 6 foot wave at the beach. Then a mountain falls on the water creating a mile high beach wave. When the “star” exploded it was like a trillion mountains fell on itself creating a big enough ripple to turn light waves into microwaves. But the wave doesn’t just happen immediately. It would probably take at least a minute for the wave to get that high. When the Big Bang happened, it took a long time for the light waves to turn into microwaves. Which is why the Big Bang happened because like it said earlier it takes along time to make microwaves so 13.8 billion years is plenty of time to make microwaves.
The fourth is that gravity created the universe. When the Big Bang happened everything expanded outward. When the universe cooled itself after 10,000 years, gravity became the dominant force and pulled everything back together to create galaxies, stars, planets, etc. Because everything had exploded outward in the Big Bang, we see these objects throughout the universe. If the Big Bang had not happened, everything would still be tightly compressed together. Think about it like this. When dynomite goes off it sends everything around it back. That is not what happened with the Big Bang. There was nothing there to send it back. To better understand it think about a bread dough with chocolate chips inside. It starts as one thing and when heat is added it expands and everything in it expands away from one another. Like when the Big Bang happened, all of the things tightly compacted together expanded like the rising of the bread.
So to answer your question: The answer is complicated. Technically it could be C, however, I think the answer they are looking for is A because that is the only one that happened immediately.
