The maximum and minimum distances between the two individuals are determined by the speed of sound and the time it takes for it to reach each individual.

Option 1 suggests that in 5 seconds, sound travels 1.8 km and in 6 seconds it travels 0.15 km, which is incorrect as sound travels at a constant speed.

Option 2 implies that within 5 seconds, sound covers 2.2 km and within 6 seconds it covers 0.20 km, which is also incorrect.

Option 3 is saying that sound travels 2.8 km in 5 seconds and 0.25 km in 6 seconds, which is inaccurate due to the constant speed of sound.

Option 4 is correct as it suggests that sound travels 1.5 km (5 seconds x 300 m/s) to reach the first person and 1.8 km (6 seconds x 300 m/s) to reach the second person. Hence, the maximum distance between them could be 1.5 km + 1.8 km = 3.3 km (if they are in the same direction from the source). The minimum distance would be 1.8 km - 1.5 km = 0.3