If I can remember I'm pretty sure it's A 
        
             
        
        
        
<span>The mass of the sun is 1.989 × 10^30 kg</span>
        
             
        
        
        
The Earth is not getting hotter because it is getting to the center of the universe.
There's two main reasons as to why the Earth is getting hotter:
1. Natural cycle
We are in a period when the Earth is in between glaciation, with one of them being behind us, and the other one being in the future. In the period in between, the Earth has the tendency to become warmer and warmer because of the change of the composition of the atmosphere, as well as the ocean currents.
2. Human activity
The people have been contributing for the increase in the warming process in the past century, and that has been done with the large release of CO2 and methane in the atmosphere. These two gases are gases that trap more heat in the atmosphere, thus resulting in an increase of the Greenhouse effect.
 
        
             
        
        
        
The inner planets were formed by rock
        
                    
             
        
        
        
Answer:
I am confused on what this is supposed to be, but if you are talking about chemicals, then your answer is sulfur.
Hoped this is what you're looking for. Sorry if it isn't. I would love to help, but it needs to be more specific.