Answer:
B) Save her money.
Explanation:
The girl's utility of saving her money = √$15 = $3.87
If the girl starts her lemonade business, the expected utility of her investment = (50% x √$5) + (50% x √$27) = (50% x $2.236) + (50% x $5.196) = $1.118 + $2.598 = 3.72
Since the utility of saving her money ($3.87) is > than the utility obtained by the investment ($3.72), the girl should save her money.