Deploying a wildcard certificate is one strategy to:

A.
Secure the certificate’s private key.

B.
Increase the certificate’s encryption key length.

C.
Extend the renewal date of the certificate.

D.
Reduce the certificate management burden.

Explanation:
A wildcard certificate is a public key certificate which can be used with multiple subdomains of a domain.
This saves money and reduces the management burden of managing multiple certificates, one for each
subdomain.
A single Wildcard certificate for *.example.com, will secure all these domains:
payment.example.com
contact.example.com
login-secure.example.com
www.example.com
Because the wildcard only covers one level of subdomains (the asterisk doesn’t match full stops), these
domains would not be valid for the certificate:
test.login.example.comIncorrect Answers:
A: A wildcard certificate is not used to secure the certificate’s private key. A private key is typically
installed into a certificates store on a server.
B: The certificate’s encryption key length is specified when the certificate is requested whether it’s a
wildcard certificate or a single domain certificate. To increase the certificate’s encryption key length, you
would need to request a new certificate. A wildcard certificate is not used increase the certificate’s
encryption key length.
C: You cannot extend the renewal date of a certificate. A certificate when requested will be valid for a set
period of time, typically one or two years. When the certificate expires, it must be renewed by requesting
a new certificate.

http://en.wikipedia.org/wiki/Wildcard_certificate