Answer:
D. Debit Deferred Revenue, $20; credit Sales Revenue, $20.
Step-by-step explanation:
Deferred revenue is a liability that represents revenue related to products that are owed to a customer but is yet to be earned.
In January, 2018, when selling the gift card, the company should have credited $50 to deferred revenue.
In February, 2018, the customer spends a fraction of the deferred revenue, so $20 should be debited to deferred revenue while the value of the purchase should be credited to sales revenue.
Therefore, the answer is D. Debit Deferred Revenue, $20; credit Sales Revenue, $20.