Consider the Scheme conditional with general form (for expressions e1, e2, e3):

(if e1 e2 e3) 

Why is it clear that if is not a function like + or string-append?

Question options:

	Because functions take one argument, and the conditional seems to take three arguments.
	Because the conditional in Scheme is a statement.
	Because the conditional expression must not evaluate all of its arguments unconditionally, but a function does evaluate all of its arguments unconditionally.
	Because we have not defined the conditional expression using (define (if x y z) ...).