Here's a problem to solve: A 72 W navigation unit on a commercial aircraft has a 24 V power supply and uses 3 A of electric current. What is the electrical resistance of the navigation unit?

Among the 4 following options, which is the correct answer?

- A: 4 ohms
 
- B: 8 ohms
 
- C: 13 ohms
 
- D: 22 ohms
 