IX. Upon his retirement, Alfredo transferred his savings derived from his salary as a marketing assistant to a time deposit with AAB Bank. The bank regularly deducted 20% final withholding tax on the interest income from the time deposit. Alfredo contends that the 20% final tax on the interest income constituted double taxation because his salary had been already subjected to withholding tax. Is Alfredo's contention correct? Explain your answer. (3%)