Fd int proportionate every yr or full int at maturity

Hello Professinal Friends....

1. My wife is a homemaker, does NOT have any salaried jobs.
2. She has 3 yrs term FD. (We have submitted Form 15G) ..... My questions.... Whether
3. (i) FULL Interest should be shown in Income Tax Return.....only AFTER 3 yrs of Maturity OR
4. (ii) PROPORTIONATE interest should be shown every yr
5. If  her total income is less than Rs2.6Lakhs for 2015-2016, then is this MANDATORY to show above FD interest in her IT RETURN? I think, filing Return itself is NOT mandatory

Please clarify points 3,4,5

Adv Thanks

Cheers

Balaji Subbu