How much current is in a circuit that includes a 9.0-volt battery and a bulb with a resistance of 4.0 ohms?

To calculate the current in a circuit using Ohm's Law, we can use the formula:

\[ I = \frac{V}{R} \]

where:
- \( I \) is the current (in amps),
- \( V \) is the voltage (in volts), and
- \( R \) is the resistance (in ohms).

In this case, we have:
- \( V = 9.0 \) volts,
- \( R = 4.0 \) ohms.

Now, we can substitute in the values:

\[ I = \frac{9.0 \, \text{V}}{4.0 \, \Omega} = 2.25 \, \text{A} \]

Rounding to two decimal places, the current is approximately \( 2.3 \) amps.

Therefore, the correct answer is **C. 2.3 amps**.