Which of the following is the correct word-formation?

The correct answer is option 4.

Key Points

•  There are four main kinds of word formation:
  • Prefixes: We add prefix before the base word. For example: "like-dislike; usual- unusual".
  • Suffixes: We add suffixes after the base or stem of a word. The main purpose of a suffix is to show what class of word it is (e.g. noun or adjective).
    • For example: terror(noun)- terrify(verb) ; pack(verb) - package(noun)
  • Conversion: Conversion involves the change of a word from one word class to another.
    • ​For example: to email (verb) - email (noun).
  • Compounding: When we use compounding, we link together two or more bases to create a new word. 
    • For example: oven-baked; baby-sit, etc.
• In the given question, a suffix is used to form a new word.
• "Detest" is a verb that means to hate someone or something very much.
• When we add the suffix "able" after the base word "detest" the new word formed will be "detestable" which is an adjective used to refer to people or things that you hate very much.

Hence, the correct answer is option 4.