Questions

All  are  correct  except  3,  as  First SAARC    Summit    was    held    in Kathmandu

The meanings of the given words are as follows:
Nefarious: (typically of an action or activity) wicked or criminal
Sloppy: careless and unsystematic; excessively casual
Flurry: a small swirling mass of something, especially snow or leaves, moved by sudden gusts of wind

Unassertive: (of a person) not having or showing a confident and forceful personality

Ignoble: not honourable in character or purpose
Modest: unassuming in the estimation of one's abilities or achievements
Subtle: (especially of a change or distinction) so delicate or precise as to be difficult to analyse or describe
Gregarious: (of a person) fond of company; sociable
Magnanimous: generous or forgiving, especially towards a rival or less powerful person
Iniquitous: grossly unfair and morally wrong
Atrocious: horrifyingly wicked
Therefore, it can be observed that option E i.e.

‘iniquitous, atrocious’ forms a synonym- synonym pair of ‘nefarious’.

'an' at the end of the first fixed segment indicates that Q, R and S can't follow the first segment. This leaves us with only one choice i.e. P. This eliminates options 2, 4, and 5.

There are only two such options: option A1and 3. Option 3 can be eliminated since part S ends with 'the' which can't be used as the end of the master statement. Hence, the correct sequence is PRSQ