On September $1,$ Howard Company purchased $$2,040$ of supplies on account and debited Supplies. At the end of the calendar year, $$1,910$ of supplies remained. 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$)?$