Tropical Wet Evergreen Forests are a type of forest that occurs in regions with high rainfall and high humidity throughout the year. These forests are characterized by dense vegetation with tall and broadleaf trees that remain green all year round. They are found in areas with a tropical climate and are typically located in coastal regions or areas with heavy rain.

Let's analyze the occurrence of Tropical Wet Evergreen Forests in the given states:

1. Arunachal Pradesh:
Arunachal Pradesh is located in the northeastern part of India and shares its border with Myanmar and Bhutan. It is known for its diverse and rich forest cover. However, Arunachal Pradesh does not have Tropical Wet Evergreen Forests. Instead, it is home to different types of forests such as Subtropical Pine Forests, Temperate Broadleaf Forests, and Alpine Forests.

2. Himachal Pradesh:
Himachal Pradesh is a state in the northern part of India and is known for its picturesque landscapes and diverse flora and fauna. Although Himachal Pradesh has a wide range of forest types, it does not have Tropical Wet Evergreen Forests. The state mainly consists of forests such as Subtropical Pine Forests, Subtropical Broadleaf Forests, and Temperate Broadleaf Forests.

3. Mizoram:
Mizoram is a state located in the northeastern part of India, sharing its borders with Myanmar and Bangladesh. It is known for its dense forests and biodiversity. Mizoram is the only state among the given options where Tropical Wet Evergreen Forests occur. The state experiences heavy rainfall throughout the year, which creates a suitable environment for the growth of these forests. The forest cover in Mizoram includes Tropical Wet Evergreen Forests along with other forest types such as Subtropical Pine Forests and Subtropical Broadleaf Forests.

Therefore, based on the analysis, we can conclude that Tropical Wet Evergreen Forests occur in Mizoram (Option C - 1 and 3 only).