Per ASC 820-10-50-2, which of the following disclosure requirements are NOT required only for 'level 3' measurements: (Select one or more)

a.		A reconciliation between the asset or liability's opening and closing balance
b.		The amount of gains or losses, included in earnings, that are related to unrealized holding gains or losses (and the line item on the income statement where these amounts appear)
c.		A description of the purchase return processes used by the entity
d.		A discussion of the sensitivity of the valuation to changes in input values