In the following question, out of the four alternatives, select the alternative which is the best substitute of the phrase.  An old unmarried woman?

Option 4 : Spinster

The correct answer is option 4, i.e. Spinster.

‘Spinster’ is a one-word substitute for the given expression ‘an old unmarried woman’. Rest of the options such as ‘masochist’ mean ‘a person who enjoys an activity that appears to be painful or tedious’, ‘septuagenarian’ means ‘a person who is between 70 and 79 years old’ and ‘sniper’ means ‘a person who shoots from a hiding place’ are irrelevant and can be eliminated.

The given word can be used in a sentence as –

The sisters were to remain spinsters for the rest of their lives.