Concept:An e-mail address must contain a username, the
@ symbol, a domain name, and a domain extension.
Explanation:A valid e-mail address has the form:
username@domainname.extension.
For example,
waeconline@yahoo.co.uk has the username
waeconline, the
@ symbol, and the domain
yahoo.co.uk.
Options A, C, and D are website addresses (URLs), not e-mail addresses, because they start with
www. and do not contain the
@ symbol.
Only an address containing
@ can receive and send electronic mail.
Therefore, the valid e-mail address is the one written in the form
user@mailserver.com.
Answer:B. waeconline@yahoo.co.uk