REC $1918$ defined several IP address ranges that can be used for private network addresses. What address is part of the Class A range used by REC $1918$ addresses?

b$.172\mathrm{.}16\mathrm{.}4\mathrm{.}13$

a$.121\mathrm{.}93\mathrm{.}18\mathrm{.}100$

d$.132\mathrm{.}62\mathrm{.}88\mathrm{.}105$

c$.10\mathrm{.}3\mathrm{.}9\mathrm{.}247$