Though the Recent Research Has Its Problems,it Has Suggested Which

Though the recent research has its problems,it has suggested which of the following trends about intelligence changes as we age?

A) Generally, intelligence is very stable, and may even increase into later adulthood.
B) Intelligence is a very static phenomenon - there are no significant changes that occur over the course of the lifespan.
C) It is very clear that intelligence is an inverted-U shaped curve - it starts low, increases through childhood into adulthood, and then shows a significant decline as we get over the age of 70 years.
D) Intelligence is a linear phenomenon - it slowly increases as we age from childhood to adulthood, getting higher the older we get.