Option 1 states that both the assertion (A) and reason (R) are individually true, and that R is the correct explanation of A. The assertion claims that the salinity of oceans is relatively higher near the equator compared to other regions. The reason provided to explain this is that the equator region has heavy rainfall, high relative humidity, and calm air.

Option 2 states that both the assertion and reason are individually true but that the reason is not the correct explanation of the assertion.

Option 3 states that the assertion is true, but the reason is false.

Option 4 states that the assertion is false, but the reason is true.

The correct answer is option 4. The assertion that the salinity of oceans is higher near the equator is incorrect. In reality, the salinity of oceans tends to be higher at the subtropical regions and lower near the equator due to factors such as the Earth`s rotation, trade winds, and evaporation. However, the reason provided in option 4, stating that the equator region has heavy rainfall, high relative humidity, and calm air, is true. This is because the equator receives a large amount of rainfall, resulting in lower salinity levels in the surrounding oceans.