$Q _ { d } = 100 - 5 P + 0.004 M - 5 P _ { R }$

$Q _ { d } = 100 - 5 P + 0.004 M - 5 P _ { R }$ ,where P is the price of good X, M is income, and $P _ { R }$ is the price of a related good, R.
-If income increases to $100,000 and the price of the related good is now $20, what is the demand function?

A) $Q _ { d } = 300 - 5 P$
B) $Q _ { d } = 400 - 10 P$
C) $Q _ { d } = 100 - 10 P$
D) $Q _ { d } = 400 - 5 P$
E) none of the above