Final answer:
Skinny caramel macchiatos, skinny cinnamon dolce, and skinny syrup lattes typically contain skim milk to reduce calorie content and make them a 'skinny' beverage option.
Step-by-step explanation:
The milk that is typically used in skinny caramel macchiatos, skinny cinnamon dolce, and skinny syrup lattes at coffee shops is C. Skim milk. The term "skinny" usually refers to the use of non-fat or low-fat milk and may also imply the use of sugar-free syrups. By choosing skim milk, these beverages are made lower in calories compared to using whole or 2% milk, which is why they are considered a 'skinny' option.