## Question 1
What is the diameter of the following binary tree?
```text
  5
 / \
6   7
   / \
  8   9
```
### Options

1. 2
Incorrect

----------------------------

2. 3
Correct
The number of edges between 6-5-7-8 is 3, which is the diameter of the tree.
----------------------------

3. 4
Incorrect

----------------------------

4. 5
Incorrect

----------------------------

---------------------------------------------

## Question 2
What is the diameter of the following binary tree?
```text
  5
   \
    6
     \
      7
       \
        8
         \
          9
```
### Options

1. 4
Correct
The number of edges between 5-6-7-8-9 is 4, which is the diameter of the tree.
----------------------------

2. 5
Incorrect

----------------------------

3. 3
Incorrect

----------------------------

4. 2
Incorrect

----------------------------

---------------------------------------------

## Question 3
What is the diameter of the following binary tree?
```text
  4
 / \
10  20
   / \
  15  7
```
### Options

1. 4
Incorrect

----------------------------

2. 5
Incorrect

----------------------------

3. 2
Incorrect

----------------------------

4. 3
Correct
The number of edges between 10-4-20-7 is 3, which is the diameter of the tree.
----------------------------

---------------------------------------------

## Question 4
What is the diameter of the following binary tree?
```text
        1
       / \
      2   3
     / \
    4   5  
   /   /
  8   9
 /   /
10  11
```
### Options

1. 5
Incorrect

----------------------------

2. 6
Correct
The number of edges between 10-8-4-2-5-9-11 is 6, which is the diameter of the tree.
----------------------------

3. 7
Incorrect

----------------------------

4. 8
Incorrect

----------------------------

---------------------------------------------