What will be the effect-understated (U), overstated (O), or no effect (N)-on the income of the present and future periods if the following errors were made? In all cases, assume that amounts carried over into 20X1 would affect 20X1 operations via the routine accounting entries of 20X1.

		Period
		20X0	20X1
1.	Revenue has been collected in advance, but earned amounts have not
	been recognized at the end of 20X0. Instead, all revenue was recognized
	as earned in 20X1.
2.	Revenue for services rendered has been earned, but the unbilled amounts
	have not been recognized at the end of 20X0.
3.	Accrued wages payable have not been recognized at the end of 20X0.
4.	Prepaid rent has been paid (in late 20X0), but no adjustment for rent used
	in 20X0 was made. The payments have been debited to prepaid rent. They
	were transferred to expense in mid-20X1.