When does a lease term begin?
A.The date on which the lessee is reasonably certain to enter into a lease contract
B.The date on which the lessor confirms its economic incentive to enter into a lease contract
C.The date on which the lessee commits to the conditions of the lease
D.The date on which the lessor makes an underlying asset available for use by a lessee
The lease term begins on the date on which the lessor makes an underlying asset available for use by a lessee.
根据企业会计准则第21号——租赁(2018)，租赁期开始日是指出租人提供租赁资产使其可供承租人使用的起始日期。这意味着租赁期开始于出租人将资产交给承租人，使其能够开始使用的那一天。因此，正确答案是：
D. The date on which the lessor makes an underlying asset available for use by a lessee
