The General Linear Demand Function Below Is Used to Answer $Q _ { d } = a + b P + c M + d P _ { R }$

The general linear demand function below is used to answer questions :
$Q _ { d } = a + b P + c M + d P _ { R }$
where Q_d = quantity demanded, P = the price of the good, M = income,
$P _ { R }$ = the price of a good related in consumption.
-If the current price of a good is $10, market demand is $Q _ { d } = 400 - 20 P$ , and market supply is $Q _ { s } = - 50 + 10 P$ , then

A) more of the good is being produced than people want to buy.
B) a lower price will increase the shortage.
C) at the current price there is excess demand, or a shortage, of 150 units.
D) Both b and c
E) All of the above