The correct answer is option 2, the Mediterranean region. In this region, mild and rainy winters are experienced, followed by warm and dry summers.

Option 1, the monsoon region, is characterized by a distinct wet and dry season. It usually receives heavy rainfall during the wet season and experiences a dry season for the rest of the year. This is not consistent with the described characteristics of mild and rainy winters followed by warm and dry summers.

Option 3, the tropical grasslands, also known as savannahs, have distinct dry and wet seasons. The dry season is characterized by little to no rainfall, while the wet season sees more significant rainfall. This is different from the mild and rainy winters, warm and dry summers described.

Option 4, temperate grasslands, have a continental climate with cold winters and hot summers. They typically have moderate rainfall distributed throughout the year, unlike the described pattern of mild and rainy winters followed by warm and dry summers.

In conclusion, the Mediterranean region is the only option that aligns with the characteristic features mentioned in the question.