To calculate the maximum range \( R \) of a projectile, we use the formula:
\[
R = \frac{v_0^2}{g} \sin(2\theta)
\]
where:
- \( v_0 = 40 \, \text{m/s} \) (initial velocity)
- \( g = 9.8 \, \text{m/s}^2 \) (acceleration due to gravity)
- \( \theta = 45^\circ \) (optimal angle for maximum range)
Since the angle for maximum range is \( 45^\circ \), \( \sin(90^\circ) = 1 \), so the formula becomes:
\[
R = \frac{(40)^2}{9.8} = \frac{1600}{9.8} \approx 163.27 \, \text{m}
\]
Thus, the maximum range is approximately \( 160 \, \text{m} \).
Therefore, the correct answer is \( 160 \, \text{m} \).