Answer:
C. Chad's willingness to pay for his second cup of latte was smaller than his willingness to pay for his first cup of latte.
Explanation:
Consumer surplus refers to the excess of price a consumer is willing to pay for a good over the price he actually ends up paying.
In the given case, Chad was willing to pay $5 for his first cup of latte. He bought the first cup for $3.75.
Thus, his consumer surplus for the first cup he purchased = $5 - $3.75
= $1.25
Similarly, his consumer surplus for the second cup of latte he purchased being, = $4.5 - $3.90
= $0.6
As can be seen, his consumer surplus has fallen in case of the second cup and also by the concept of diminishing marginal utility by which utility derived after each successive unit of consumption falls, Chad was willing to pay lesser i.e $4.5 instead of $5 for the second cup of latte.
Hence, Chad's willingness to pay for his second cup of latte was smaller than his willingness to pay for his first cup.