Complete this indirect proof of Theorem $11-1-1$
Given: $\ell$ is tangent to $\odot A$ at point $B$
Prove: $\ell \perp \overline{A B}$
Proof: Assume that $\ell$ is not $\perp \overline{A B}$. Then it is possible to draw $\overline{A C}$ such that $\overline{A C} \perp \ell .$ If this is true, then $\triangle A C B$ is a right triangle. $A C < A B$ because a. $\underline{?} .$ since $\ell$ is a tangent line, it can only intersect $\odot A$ at $\mathbf{b} . \quad ?,$ and $C$ must be in the exterior of @A. That means that $A C > A B$ since $\overline{A B}$ is a c. $?$. This contradicts the fact that $A C < A B$. Thus the assumption is false, and d. $?$