This question is incomplete; here is the complete question:
The rule that the subject and verb must be the same in number is called subject-verb ________________
The correct answer is Subject-verb Agreement
Explanation:
In grammar, one of the most basic rules is that the subject and verb must agree in number. This rule is known as subject-verb agreement and implies a singular verb should be preceded by a singular subject and vice versa. For example in "My mother cooks lasagna" the subject "my mother" is singular and the verb form "cooks" is also singular, this makes the sentence grammatically correct, while the sentence "They sings in the church" will be considered incorrect as the subject is plural and the verb form is singular.