Which of these remarks about formal parameters is correct?

a) A formal parameter is a kind of place holder that is filled with the argument at the time of call to the function.
b) A call-by-value formal parameter is a global variable that is initialized to the
value set just before the function is called.
c) A call-by-reference formal parameter is modeled on a substitution mechanism.
The argument should be an expression, not a variable, since there is never a need
to assign such a variable.
d) The & (ampersand) character is used to indicate call-by-reference. This is done by placing the & after the type name which is followed by the parameter name in the
definition of the parameter in the function header.
e) The argument corresponding to a call-by-value parameter cannot be changed by anything that happens in the function call.

a) A formal parameter is a kind of place holder that is filled with the argument at the time of call to the function.
d) The & (ampersand) character is used to indicate call-by-reference. This is done by placing the & after the type name which is followed by the parameter name in the
definition of the parameter in the function header.
e) The argument corresponding to a call-by-value parameter cannot be changed by anything that happens in the function call.