The reagent (A) is:

a)

LAH

b)

HI+P

c)

d)

(d)

a. LAH reduces both ester and acid to alcohols

b. HI + P reduces both ester and acid to alkane

c. reduces only ester to aldehyde and alcohol

d.  selectively reduces acid to alcohol (although it can also reduce ester to alcohols) but acid group is reduced in the presence of esters

So the answer is (d)