The correct answer is option 3: Rainwater collected after 30 to 40 minutes of raining is not suitable for drinking because it is deficient in minerals.

Option 1: Rainwater collected after a short duration of rain does not contain bacteria and dirt. In fact, rainwater is relatively clean when it falls from the sky, as it does not contain the pollutants found on the ground.

Option 2: While it is true that rainwater can contain dissolved toxic chemicals, this is not the main reason why rainwater collected after a short duration of rain is not suitable for drinking. Toxic chemicals are typically present in rainwater due to air pollution and industrial activities, and their concentration tends to be higher in areas with heavy pollution.

Option 4: Rainwater collected after a short duration of rain is not necessarily acidic. The acidity of rainwater is influenced by various factors, including air pollution and the presence of natural acids in the atmosphere. However, the duration of rainfall alone does not determine the acidity of rainwater.

Therefore, the most accurate explanation is that rainwater collected after 30 to 40 minutes of raining is not suitable for drinking because it is deficient in minerals. Rainwater is naturally low in minerals, and by collecting it after a short duration of rain,