## Question 1 What is the lowest common ancestor of $4$ and $7$ in the following binary search tree? ```text 5 / \ 4 8 / \ 7 9 ``` ### Options 1. 5 Correct ---------------------------- 2. 4 Incorrect ---------------------------- 3. 9 Incorrect ---------------------------- 4. 8 Incorrect ---------------------------- --------------------------------------------- ## Question 2 What is the lowest common ancestor of $3$ and $6$ in the following binary search tree? ```text 9 / \ 6 11 / \ 3 12 ``` ### Options 1. 11 Incorrect ---------------------------- 2. 12 Incorrect ---------------------------- 3. 6 Correct Since a node is a descendant of itself, the lowest common ancestor of $3$ and $6$ is $6$. ---------------------------- 4. 3 Incorrect ---------------------------- --------------------------------------------- ## Question 3 What is the lowest common ancestor of $1$ and $3$ in the following binary search tree? ```text 5 / \ 2 6 / \ \ 1 3 7 ``` ### Options 1. 5 Incorrect ---------------------------- 2. 6 Incorrect ---------------------------- 3. 7 Incorrect ---------------------------- 4. 2 Correct ---------------------------- ---------------------------------------------