Which code segment should you insert at line 04?

You develop a webpage by using HTML5. You create the following markup and code: (Line numbers are
included for reference only.)

You need to ensure that the values that users enter are only numbers, letters, and underscores, regardless of
the order.
Which code segment should you insert at line 04?

A.

B.

C.

D.

Explanation:
https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/RegExp