Mehrab is one of "the" "most" intelligent boys "of " the "science" class. (FInd out which Quoted part of the following sentences has an error)

I do not know where "could" "he" have "gone" so "early" in "the" morning. (FInd out which Quoted part of the f...

Malnutrition "is a major" cause of death in "those countries" where the cultivation of rice "have" been impede...

To Smell the rat ( Choose the one which best express the meaning of the given idiom)

To take a leap in the dark- ( Choose the one which best express the meaning of the given idiom)

To get into hot waters- ( Choose the one which best express the meaning of the given idiom)

which series is correct when making a presentation --