The correct option is D spread
Let’s examine the sentence: “Because coughing spread germs and Ram is coughing, Ram is spreading germs.” The gerund ‘coughing’ is followed by the verb ‘spread’ and the sentence is of simple present tense as indicated by the use of ‘is’ later. Gerunds are verbs that act as nouns. Here, ‘coughing’ is acting as a singular noun and subject of the verb ‘spread.’ So, according to subject-verb agreement for simple present tense, the verb ‘spread’ should be in suffixed by an ‘s.’ In a simple present sentence where singular noun or pronoun is the subject, verbs end in -s or -es depending on the way the verb ends. So, ‘spread’ should be replaced by ‘spreads’ in this sentence. Hence, the word or phrase that must be changed for the sentence to be correct is indicated by Option B. Option B is the correct answer.