A key feature that distinguishes a Federal Direct Subsidized Loan from an Unsubsidized Loan is that interest does *not* accrue while the student is:

The correct answer to the question "A key feature that distinguishes a Federal Direct Subsidized Loan from an Unsubsidized Loan is that interest does *not* accrue while the student is:" is Option C: Enrolled at least half-time.

The other options — A) Enrolled less than half-time, B) In an approved forbearance period, D) In a grace period *after* repayment has begun — are incorrect for this College Advising question. As explained above: For Federal Direct Subsidized Loans, the government pays the interest while the student is enrolled at least half-time and during the grace period, making it a more favorable loan option.