C. The force is a constant change, because her position on the Ferris wheel will constantly change. I believe this is the answer, but use sources to double check. I might use different vocab. then your teachers.

Explanation
the density of an object is given by:

Step 1
find the volume of the bar
a)find the volume of the rectangular bar.
the volume of a rectangular prism is given by:

replace

Step 2
now,
Let

replace in the formula

therefore, the answer is

I hope this helps you