The Exposure Coefficient $b = \frac { \operatorname { Cov } ( P , S ) } { \operatorname { Var } ( S ) }$

The exposure coefficient $b = \frac { \operatorname { Cov } ( P , S ) } { \operatorname { Var } ( S ) }$ in the regression $P = a + b \times S + e$ is:

A) A measure of how a change in the exchange rate affects the dollar value of a firm's assets.
B) Has a value of zero if the value of the firm's assets is perfectly correlated with changes in the exchange rate.
C) both a and b
D) none of the above