Liza has forgotten her password to an online bookstore. The web application asks her to key in her email so that they can send her the password. Liza enters her email liza@yahoo.com’. The application displays server error. What is wrong with the web application?

A.
The email is not valid

B.
User input is not sanitized

C.
The web server may be down

D.
The ISP connection is not reliable

Explanation:
All input from web browsers, such as user data from HTML forms and cookies, must be stripped of special characters and HTML tags as described in the following CERT advisories:
http://www.cert.org/advisories/CA-1997-25.html
http://www.cert.org/advisories/CA-2000-02.html