Which sentence is grammatically correct?

• A. The squads mission is critical.
• B. The squad's mission is critical.
• C. The squad mission is critical.
• D. The squad's missions are critical.

Answer: (B)

Ownership and agreement are being tested here. Use the possessive form to show who owns the mission: squad’s adds the apostrophe-s to a singular noun to indicate possession. The word mission is singular, so the verb must also be singular: is. Put together, the sentence reads: The squad’s mission is critical.

Why the others don’t fit: without the apostrophe, squad carries no possessive mark, which misstates ownership. The squad mission version lacks possession and sounds off in standard English. The squad’s missions are critical talks about multiple missions, which would require a plural verb (are) and changes the meaning.