On September $1,$ Griffin Company received $$27,900$ for six months of rent in advance. Griffin credited Deferred Rent Revenue. If the appropriate adjusting entry is not made at the end of the year, what will be the effect on:

$($a$)$ Income statement accounts $($overstated$,$ understated, or no effect$)?$

$($b$)$ Net income $($overstated$,$ understated, or no effect$)?$

$($c$)$ Balance sheet accounts $($overstated$,$ understated, or no effect$)?$