mr. hadi : Let me introduce myself. my name is mr. hadi. im your new math teacher students : how do you do, mr. hadi? we are glad to meet you from the dialog we

mr. hadi : Let me introduce myself. my name is mr. hadi. im your new math teacher
students : how do you do, mr. hadi? we are glad to meet you

from the dialog we know that...
a. the students have already known mr. hadi
b. mr. hadi has already known the students
c. mr. hadi and the students have known each other
d. Mr. hadi and the students haven't known each other.
e. mr. hadi has taught math before