Answer:
The answer is A. Treasury Bills
Step-by-step explanation:
Treasury bills (T bills) are short-term security(debt security) backed by the national government. The maturity period is always less than a year or a year at maximum.
Since the customer's horizon is 3 months, he should walk up to his bank and buy treasury bills. It is always risk free.
Tbills is usually sold at discount to par value i.e the purchase price is less than the face value(value at maturity) of the bill.