Line integral anyone?

A line integral is a definite integral where you integrate some function $f(x,y,z)$ along some path. For which of the following would it be appropriate to use a line integral?

A. The total work done on a charge moving in a circle of radius $R$ on the $xy$-plane centered at the $z$-axis by a charge at the coordinate $(R,R,R)$

B. The area under the curve $y=x^2$ between $x=2$ and $x=5$

C. The total radiation absorbed by a person walking at a uniform rate around an ellipse with minor axis of length $a$ and major axis of length $b$, with a radiation source at the coordinate $(b,a)$