confused over answer given so plz explain!!!

II ?

which has got greater -I effect -COR or -CO2R?

Actually its not so much about -I, but pertaining to resonance....

IN COO- the C=O is already involved in resonance with the other Oxygen, so it cannot seek as much to the carbanion as only -C=O can...

infact the second compound seems to yield the more stable carbanion ! thats because the hunger for electrons of one of the C=O groups has been reduced by the resonance effect of the ethoxy group ! (childish explanation, lol )