Concept:Check each underlined part for errors in subject-verb agreement, tense, and preposition use.Explanation:Part (a): “Raman and Mitali” is a plural subject.Part (b): “have been married” correctly matches the plural subject.Part (c): “for 20 years” correctly uses “for” with a duration.All underlined parts are grammatically correct.Answer:There is no error; the correct option is (d).