Which sentence demonstrates correct subject-verb agreement?

✓ Correct Answer: Option C

In option C, 'Every one' is singular, so the singular verb 'has completed' is correct. In A, 'list' is singular, requiring 'is'. In B, 'professor' (closer subject) is singular, requiring 'was'. In D, 'number' in 'a number of' is plural, requiring 'have been published'.