Answer:
D) 10
Explanation:
Joseph is consuming pizzas at $5 per slice and sodas as $1 per soda.
If the marginal utility of the third slice is 50, then the utils per dollar = 50 / $5 = 10 utils per dollar.
Since the soda costs $1, and it provides the same utils per dollar as the pizza, then the marginal utility = $1 x 10 utils per dollar = 10 utils