Step 1: Understanding the Concept:
This question tests spelling. You need to identify the word that is not spelled correctly among the given options.
Step 2: Detailed Explanation:
Let's examine each option:
(A) Commander: This spelling is correct. It refers to a person in authority, especially over a body of troops or a military operation.
(B) Commandent: This spelling is incorrect. The correct spelling for the officer in charge of a particular force or institution is Commandant.
(C) Commercial: This spelling is correct. It relates to commerce or business.
(D) Commissioner: This spelling is correct. It refers to a person appointed to a role on or by a commission.
Step 3: Final Answer:
The word 'Commandent' is misspelt. The correct spelling is 'Commandant'.