Answer:
a. Cash basis $15,000
b. Accrual basis $2,500
Explanation:
Under the cash basis of accounting, expenses are recorded or recognized in the books not necessarily when incurred but when cash is paid. This is not in line with the matching concept which requires that expenses be recognized the  period it is incurred as well as the resulting revenue.
Hence, the $15,000 paid on January 1 Â would have been recognized as an expense for the two months ending February 28 using the cash basis.
Using the accrual basis, monthly expense
= $15,000/12
= $1,250
Hence advertising expense for 2 months
= 2 * $1,250
= $2,500