Verbal Reasoning - Mental Ability Questions

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
efg _ _ eff _ ghhe _ eff _ gggh _ h

Pointing towards a man, Ritika said "He is the son of my grandfather's only son". How is Ritika related to that man?

If STUDENT is coded as 103, what is the code for SCHOOL?

Pointing to a photograph of a lady, Vishal says, "She is the sister­in­law of my grandfather's daughter". How is the lady in the photograph related to Vishal?

In a certain code language, "VERBAL" is written as "KZAQDU". How is "CURIOUS" written in that code language?

If BOULDER is coded as ZMSJBCP, then how will ELK be coded as?

If OUTLINE is coded as QWVNKPG, then how will MAN be coded as?

Sanjeev scored the highest marks in the class. Rahul scored more than Nirbhay but lesser than Sameer. Arpit scored more than Rahul. Who got the 4th Rank out of the five?