John Is Going to Spend All of His Income

John is going to spend all of his income. For the last unit of Good X consumed John gets 20 utils and for the last unit of Good Y consumed he gets 10 utils. The price of Good X is $4. The price of Good Y is $2. If John wants to maximize his utility he should

A) continue to purchase the same amount of Good X and Good Y.
B) increase the consumption of Good X and decrease the consumption of Good Y.
C) decrease the consumption of Good X and increase the consumption of Good Y.
D) decrease the consumption of Good X and decrease the consumption of Good Y.