u are assuming d is a perfect sq
in 2) max value of d is 36 so we know 1,4,9,16,25 are less d
1) d can be < or > or = 25

perfect sq are 1,4,9,16,25,36 etc
A) option A says 23 < d < 33
if d=24 then perfect sq less than d are 1,4,9,16
id d=26 then perfect sq less than d are 1,4,9,16,25

hence insuff

B)option B says 27 < d < 37

if d=28 then perfect sq less than d are 1,4,9,16,25
if d=36 then perfect sq less than d are 1,4,9,16,25

hence suff
ans is B