You can use a ball-and-stick model to show the atomic structure of a molecule. Ethanol has the chemical formula C2H6O. Its model is shown below.

To create a ball-and-stick model of butanol (C4H10O), you will need to represent the atoms in the molecule as follows:

1. **Carbon (C)** is typically represented by a black circle.
2. **Hydrogen (H)** is represented by a gray circle.
3. **Oxygen (O)** is represented by a red circle.

For butanol (C4H10O):
- There are 4 carbon atoms (C) → You will need **4 black circles**.
- There are 10 hydrogen atoms (H) → You will need **10 gray circles**.
- There is 1 oxygen atom (O) → You will need **1 red circle**.

Now, we can match the materials with the number needed:

- A (Black circle for Carbon) → 3 (because you need 4 carbon atoms)
- B (Gray circle for Hydrogen) → 2 (because you need 10 hydrogen atoms)
- C (Red circle for Oxygen) → 1 (because you need 1 oxygen atom)

So the final mapping is:
- A. Black circle → 4
- B. Gray circle → 10
- C. Red circle → 1