The correct answer is B. the sum of your deductible contributions exceeds $300.
As of the 2021 tax year, if you are filing an individual tax return and want to claim a deduction for charitable contributions, you must itemize your deductions if your total charitable contributions exceed $300 (or $600 for married couples filing jointly). If your contributions are $300 or less, you can claim the charitable deduction as an above-the-line deduction on your tax return without having to itemize.