Which of the following IP addresses are recommended for private networks? $($Choose all that apply.

a$.$ Any IP addresses that begin with $10$ as their first octet

b$.$ Any IP addresses that begin with $172$ as their first octet

c$.$ Any IP addresses that begin with $192\mathrm{.}168$ as their first two octets

d$.$ Any IP addresses that begin with $192$ as their first octet