We know that Jeff's birthday falls on $$25^{\text {th$$ of June; we need to find the month of Harry's birthday if he was born exactly 400 days after Jeff was born.

After 365 days the same date i.e. $$25^{\text {th$$ June will come (We have assumed that a non- leap year followed after the birth year of Jeff).

The remaining days are $400-365=35=30+5$ i.e. a complete month and 5 more days, so we get $$25^{\text {th$$ July +5 more days $$=30^{\text {th$$ July.

Note: - even if we consider a leap year after the birth year of Jeff, the $$400^{\text {th$$ day will be the next day i.e. $$31^{\text {st \mathrm{July}$$, so the month will remain the same.

Hence the month in which Harry was born was July, so the answer is (B).