On April 1, Jiro Nozomi created a new travel agency, Adventure Travel. The following transactions occurred during the company's first month.
[Transaction details given]. Which of the following statements is true?
a) Prepaid insurance of $161 has expired this month.
b) At the end of the month, $600 of office supplies are still available.
c) This month's depreciation on the computer equipment is $400.
d) Employees earned $350 of unpaid and unrecorded salaries as of month-end.
e) The company earned $2,300 of commissions that are not yet billed at month-end.