Consider the following statements:

(1). To check whether a function is called with the correct number of arguments we can use lexical analyser.

(2). Underscore characters (_) may appear in the middle of identifiers, but not at the beginning or end, this can be checked using a lexical analyser.

(3). To make sure that every variable has been declared before it is used in the program we need a push down automata.

(4). To make sure assignment statements ends with a semicolon we need syntax analyser.

Which of the above statement/s is/are correct?