UPSC CDS English Spotting the Errors Part 2 Questions

There is a difference between “so” and “so that”. Both of these words are adverbs. They are used with a subject and a verb to make a clause. “So that” tells us for what purpose something is done. Here the ‘prism’ refracts light ‘so that’ it spreads out and not ‘so it’ spreads out. Thus, option (b) is correct.