Indian Institute of Foreign Trade 2014 Solved Paper

(c) Mumble means not speaking clearly. Mumbling leads to unclear and indistinct conversation. The option that is closest in the relationship to this is option (c) as scribbling leads to illegible handwriting. Rest of the options is related in some different manner.
Swagger means to walk or behave in a very confident and arrogant way whereas timid shows a lack of courage. So they are opposite to each other.
Exacerbate means make something worse and cure is its opposite.
Drizzle is light rain whereas downpour is heavy rainfall.