Use the Following General Linear Demand Relation $Q _ { d } = 100 - 5 P + 0.004 M - 5 P _ { R }$

Use the following general linear demand relation: $Q _ { d } = 100 - 5 P + 0.004 M - 5 P _ { R }$ where P is the price of good X,M is income,and $P _ { R}$ is the price of a related good,R.Income is $80,000,and the price of the related good is $40.Also let consumers' tastes change so that consumers now demand 100 more units at each price.When the price of the good is $50,how many units of the good are demanded?

A) 70
B) 200
C) 220
D) 100
E) none of the above