Which sentence best demonstrates grammaring?

• A. She work project 3 month
• B. She'll be working on the project for 3 months.
• C. They goes to the library.
• D. We has finished the assignment.

Answer: (B)

Expressing ongoing future actions with the correct tense and proper subject-verb agreement is what this item tests. The best sentence uses will be working, the future continuous form, which shows an action that will be in progress over a period of time in the future. The contraction She'll stands for She will, and the subject matches the singular form. The phrase for 3 months marks a duration, which pairs naturally with the future continuous to describe something that will be happening during that entire period.

Why the other options don’t fit as well: one sentence lacks an auxiliary verb and uses incorrect word order, so it doesn’t express a proper future action. Another sentence has a subject-verb mismatch with a plural subject and a singular verb (goes instead of go). The last sentence also has subject-verb disagreement and would require a different structure (we have finished or we finished) to be grammatically correct.