Option 1: The Mediterranean region is characterized by a Mediterranean climate, which typically experiences dry summers and wet winters. Therefore, rainfall does not occur throughout the year in this region.

Option 2: The equatorial region experiences consistent rainfall throughout the year. This is due to the low pressure and convergence of trade winds, causing a continuous uplift of air and subsequent condensation and precipitation.

Option 3: The tropical region also experiences rainfall throughout the year, similar to the equatorial region. This is because of the warm temperatures and high humidity, creating conditions favorable for constant rainfall.

Option 4: The temperate region, including areas like Europe and North America, generally experiences distinct seasons with varying patterns of rainfall. Therefore, rainfall does not occur throughout the year in this region.

Therefore, the correct answer is option 2, the Equatorial region is where rainfall occurs throughout the year.