Can you explain the calculus behind this math in detail? Please show the math for each step in a clear and simple way. Thanks. What is the value of B_(2V)(T) when N_
(A) is equal to -2\pi and the integral from 0 to \sigma of [0-1]r^(2)dr is equal to -2\pi?

A) -2\pi
B) 0
C) \sigma
D) None of the above