In which of the following cases should Paul, the executor of his father's estate, waive his executor's fee?'

I. Paul is a 35% taxpayer and his father's estate is beneath the applicable exemption amount.

II. Paul is the only heir of his father's estate, which is valued at $5,000,000.

III. The primary beneficiary of the estate is Paul's son, who is struggling to afford medical school; Paul is wealthy.

1. I Only
2. II Only
3. III Only
4. I and III only
5. All of the above