Identify the sentence that has correct subjectdash–verb agreement.
a. both of my dogs is very gentle.
b. boths of my dogs are very gentle.
c. both of my dog is very gentle.
d. both of my dogs are very gentle.

d. Both of my dogs are very gentle.

This sentence is in the correct form, grammatically. In subject-verb agreement, the words several, few, both, many take the plural form of the verb.
Examples:
1. Several of the boys in the classroom have been playing all day long.
2. Few cats ate their meal.
3. Many buildings in town were burned.