JAMB Use of English 1995 Question 27

Select the option that best explains the information conveyed in the sentence: My son, who is in the U.S. A. is studying Engineering

1. A.my only son is in the U.S.A studying Engineering
2. B.one of my sons is in the U.S.A. studying Engineering
3. C.my sons are in the U.S.A but only one is studying Engineering
4. D.only my son is in U.S.A studying Engineering