If management report truthfully, what economic events are likely to prompt the following accounting changes?

a) Increase in the estimated life of depreciable assets.

b) Decrease in the uncollectible allowance as a percentage of gross receivables.

c) Recognition of revenues at the point of delivery, rather than at the point cash is received.

d) Capitalization of higher proportion of software R&D costs.

give an answer with your explain!