The most pleasant elements i.e. summer temperatures rarely above 40o and winters are fairly mild, occur in the

tropical mid-latitude zone
sub-tropical latitude zone
temperature mid-latitude zone
sub-temperature latitude zone

The correct answer is: C. temperature mid-latitude zone.

The temperature mid-latitude zone is a region of the Earth’s atmosphere that lies between the tropics and the polar regions. It is characterized by temperate climates with warm summers and cool winters. The most pleasant elements i.e. summer temperatures rarely above 40o and winters are fairly mild, occur in this zone.

The tropical mid-latitude zone is a region of the Earth’s atmosphere that lies between the tropics and the subtropics. It is characterized by tropical climates with hot summers and warm winters. The sub-tropical latitude zone is a region of the Earth’s atmosphere that lies between the tropics and the temperate zones. It is characterized by subtropical climates with warm summers and mild winters. The sub-temperature latitude zone is a region of the Earth’s atmosphere that lies between the temperate zones and the polar regions. It is characterized by sub-polar climates with cool summers and cold winters.

The temperature mid-latitude zone is the most pleasant region of the Earth’s atmosphere because it has a temperate climate with warm summers and cool winters. The summers are not too hot and the winters are not too cold. This makes it a good place to live and work.