Explanation:
Before moving to the answer, let's understand the meaning of consumer surplus.

Consumer Surplus: It is the difference between the total amount that consumers are willing and able to pay for a good or service and the total amount that they actually pay. It is the benefit that consumers receive for paying less than the maximum price they would be willing to pay.

Now, let's solve the problem step by step.

Given:
Total utility = 212
Amount spent = 100

Calculating Consumer Surplus:
To calculate consumer surplus, we need to find the maximum amount that the consumer is willing to pay for the product, which is equal to the total utility.

Therefore, maximum amount consumer is willing to pay = 212

Now, we need to find the difference between the maximum amount the consumer is willing to pay and the amount the consumer actually pays.

Consumer Surplus = Maximum amount consumer is willing to pay - Amount consumer actually pays

Consumer Surplus = 212 - 100

Consumer Surplus = 112

Therefore, the consumer surplus is 112.

Answer:
The correct option is 3. 112.