Melody's Piano School Operations for the Month of May Were

Melody's Piano School operations for the month of May were limited to the following transactions: Provided $800 of piano lessons to students who paid in cash.
Provided $200 of piano lessons on account.
Collected $600 from students who took piano lessons during April.
Paid April's piano rental bill of $200.
Received May's piano rental bill of $300 and set it aside for payment in June.
Assuming the company uses accrual basis accounting,what is net income for May?

A) $800.
B) $600.
C) $700.
D) $1,200.