The correct answer is D. Here I am.
The other options are incorrect because they do not follow the rules of English grammar. The verb “to be” must agree with the subject of the sentence. In this case, the subject is “I”, which is a singular pronoun. Therefore, the verb must also be singular. The only option that is singular is “Here I am.”
The other options are also incorrect because they do not make sense in the context of the question. The question is asking where Johny is, and the answer “There I am” does not provide any information about Johny’s location. The answer “There am I” is also incorrect because it is not grammatically correct. The answer “Here am I” is the only option that provides both accurate information about Johny’s location and follows the rules of English grammar.