A, stroke. I know this would happen only from watching too much House (lol) but I know for fact that a heart attack would be caused by a blood clot if it gets stuck in an actual heart vessel.
The sun. lol. It is closer to Earth, therefore bigger to us, and not just a small point of light.

Actually Welcome to the concept of Efficiency.
Here we can see that, the Input work is given as 2.2 x 10^7 J and the efficiency is given as 22%
The efficiency is => 22% => 22/100.
so we get as,
E = W(output) /W(input)
hence, W(output) = E x W(input)
so we get as,
W(output) = (22/100) x 2.2 x 10^7
=> W(output) = 0.22 x 2.2 x 10^7 => 0.484 x 10^7
hence, W(output) = 4.84 x 10^6 J
The useful work done on the mass is 4.84 x 10^6 J
Explanation:
Blue or violet light has the shortest wavelength. White light is a combination of all colors in the color spectrum.