Which of the following expressions of the sentence "The present Prime Minister of Viet Nam is Nguyen Tan Dung" DOES NOT have constant reference?5/30Which of the following expressions of the sentence "The present Prime Minister of Viet Nam is Nguyen Tan Dung" DOES NOT have constant reference?Nguyen Tan DungViet NamThe present Prime Minister of Viet Nama and bGiải thíchChọn đáp án C