A student is repeatedly calling a function file but gets no output. She has checked the file repeatedly so finally she asked her teacher about it$.$ The teacher checked everything and finds the error and gives her a scolding. What is a silly mistake?

$$ a$.$ She was calling a script file

b$.$ She has called a $.$m file

c$.$ She was calling the wrong function

d$.$ She has placed a semicolon at the end of the line which computes the desired values