Only one of the approaches to ethical reasoning has as its central tenet that actions are more right if they promote more happiness, more wrong as they produce unhappiness. which approach applies

I believe the answer is: End-result ethics. 

End-result ethics refers to a moral standard in which the standard of right or wrong would be determined by the final outcome of your actions rather than the process.
In End-result ethics, as long as the person feel happiness/positive benefits in the end, all of their actions would be considered as right even though it might cause some collateral damages along the way.

This is what i found on google “eightin 1997, the mccaughey septuplets were born in carlisle, iowa. multiple births of as many as eight babies have been born alive, the first set on record to the chukwu family in texas in 1998; one died and seven survived. in 2009, a second set, the suleman octuplets, were born in bellflower, california.” i was surprised about this . i don’t want to have that many babies .