Answer:
(c) 8 units of utility
Step-by-step explanation:
You want the marginal utility of the third Laddu, if the first two yield 18 and 12 units of utility, and the total utility of 3 Laddu is 38 units.
The marginal utility of a Laddu is the utility added by adding a Laddu.
After the first, there are 18 units of utility. After the second, there are 18+12=30 units of utility. After the third, there are 38 units of utility.
Adding the third Laddu added 38-30 = 8 units of utility.
The marginal utility of the third Laddu is 8 units of utility, choice C.