Neville, Has a Friend Named Marmaduke

Neville, has a friend named Marmaduke.Marmaduke has the same demand function for claret as Neville, namely q = .02m - 2p, where m is income and p is price.Marmaduke's income is $8,000 and he initially had to pay a price of $40 per bottle of claret.The price of claret rose to $80.The substitution effect of the price change

A) reduced his demand by 80.
B) increased his demand by 80.
C) reduced his demand by 16.
D) reduced his demand by 144.
E) reduced his demand by 26.