To solve this problem, we will use the Doppler effect formula for sound.$\\$The formula for the observed frequency $f'$ when the source and observer are moving towards each other is:$\\ f' = f \left( \frac{v + v_o}{v - v_s} \right) \\$Where:$\\$• $f$ is the frequency of the source (400 Hz).$\\$• $v$ is the velocity of sound in air (340 m/s).$\\$• $v_o$ is the velocity of the observer (16.5 m/s).$\\$• $v_s$ is the velocity of the source (22 m/s).$\\$Substitute the known values into the formula:$\\ f' = 400 \left( \frac{340 + 16.5}{340 - 22} \right) \\$Calculate the terms in the fraction:$\\ f' = 400 \left( \frac{356.5}{318} \right) \\$Simplify the fraction:$\\ f' = 400 \times 1.1217 \\$Calculate the observed frequency:$\\ f' \approx 448.68 \\$Since the frequency must be an integer, we round it to the nearest whole number:$\\ f' \approx 449$ Hz$\\$However, considering the options provided, the closest match is 448 Hz.$\\$Therefore, the frequency heard by the driver of the second car is $448$ Hz.$\\$This corresponds to Option 3.