We know from the triangle inequality that the last side, $s$, fulfills $s+7\textgreater12$. $P=s+7+12\textgreater12+12$. Therefore, $P\textgreater24+1=25$ 
For $\triangle ABC$, all its side lengths are integer. The primeter of $\triangle ABC$ with a side of length $12$ and a side length of $7$ is at least ． 
[A] $$24$$ 
[B] $$25$$ 
[C] $$26$$ 
[D] $$27$$ 
[E] $$28$$ 