A company purchased 50,000 worth of office supplies on January 1st and had 15,000 of office supplies still on hand at year-end. If the initial purchase of supplies entry on January 1st was to debit office supplies expense and to credit cash for 50,000. The adjusting entry on December 31 will be:

A) Office supplies 15,000 Office supplies expense 15,000

B) Office supplies expense 15,000 Office expense 15,000

C) Office supplies 35,000 Office supplies expense 35,000

D) Office supplies expense 35,000 Office supplies 35,000

Please explian the answer