Answer:
B. The Mountain Bike
Explanation:
We can find the cost of each util for the two options.
The Porsche costs $60,000 and represents 1,200 utils, therefore:
$60,000 / 1,200 = $50
This means that each util costs $50 for the Porsche.
Now, for the mountain bike:
$800/20 = $40
This means that each util costs $40 for the Mountain Bike.
Rational people think at the margin: Sandra will purchase the option that gives her the greatest marginal benefit, in this case, the mountain bike ($40 per util vs $50 per util).