Answer:
D) should buy less b and more a.
Explanation:
the marginal utility obtained from consuming the last unit of A = 16 / $2 = 8 utils per dollar
the marginal utility obtained from consuming the last unit of B = 24 / $4 = 6 utils per dollar
Ms. Thomson should purchase less units of B or more units of A until the marginal utility provided by each good is equal.