I think speed is the answer
Talking about a quantity of inertia is exactly the same as talking about a quantity of mass. So, if the boxes are anywhere near the same size, then the box of books has <u><em>more</em></u> inertia than the box of cotton balls, because books have more mass than an identical volume of cotton.
"The process used by scientific investigations is the scientific method. This involves making an observation, stating a question, formulating a hypothesis, conducting an experiment and analyzing the results to form a conclusion. "
I would most likely go with B. but im not 100% sure
PART A)
By Snell's law we know that

here we know that



now from above equation we have


so it will refract by angle 39.3 degree
PART B)
Here as we can see that image formed on the other side of lens
So it is a real and inverted image
Also we can see that size of image is lesser than the size of object here
Here we can use concave mirror to form same type of real and inverted image
PART C)
As per the mirror formula we know that



so image will form at 30 cm from mirror
it is virtual image and smaller in size