If each vowel of the word WITHOUT is changed to the previous letter of the English alphabets and each consonant is changed to the next letter of the English alphabet, and then the alphabets thus formed are arranged in alphabetical order from left to right, which of the following will be exactly in the middle?

Select the most appropriate antonym of the given word.

SPARSE

The science of colours.

The two parties signed a lengthy _________.

It took a lot of time in making both of them come to a comfortable mutual ___________.

Deadlock 

Exhilarate

Perpetual

Select the most appropriate word for the given group of words. 

A slowly moving mass or river of ice

A lady who remains unmarried 

Select the most appropriate meaning of the given idiom. "Go down like a lead balloon"

In the following questions, out of the four alternatives, choose the one which best expresses the meaning of the given word as your answer.