Final answer:
d. Regions in Canada help us understand its climate diversity by examining variations in weather patterns.
Step-by-step explanation:
Regions help us to understand Canada's diversity of climate by examining variations in weather patterns (Option D). Different regions in Canada experience different weather conditions due to factors such as latitude, elevation, wind systems, ocean currents, and mountain barriers.
For example, the coastal regions of British Columbia have a mild and rainy climate while the prairie regions in the interior have a drier and more continental climate.