1. **State the problem:** Find the intersection of sets $A = \{11, 7, -5, 12, 1, 2, 3\}$ and $B = \{1, 2, 6, 9, 11\}$. 2. **Recall the definition of intersection:** The intersection $A \cap B$ is the set of all elements that are in both $A$ and $B$. 3. **Identify common elements:** Check each element of $A$ to see if it is also in $B$. - $11$ is in both $A$ and $B$. - $7$ is not in $B$. - $-5$ is not in $B$. - $12$ is not in $B$. - $1$ is in both $A$ and $B$. - $2$ is in both $A$ and $B$. - $3$ is not in $B$. 4. **Write the intersection set:** $A \cap B = \{1, 2, 11\}$. 5. **Answer:** The correct intersection is $\boxed{\{1, 2, 11\}}$.