Step 1: Recall what gives carrot its colour.
Carrot is a root vegetable with a deep orange colour. This colour comes from a pigment called beta carotene, which is present in the carrot in large amounts.
Step 2: Link beta carotene to a vitamin.
Beta carotene is called a provitamin because the human body can convert it into an active vitamin. Cells in the intestine wall and the liver split beta carotene and turn it into retinol, which is Vitamin A. So eating carrot supplies the body with the raw material it needs to make Vitamin A.
Step 3: Check the other options.
Vitamin C is mainly found in citrus fruits like orange and lemon, and also in amla and guava, not in carrot in a major way.
Vitamin D is made in the skin using sunlight, and is also found in fish liver oil and egg yolk, not in carrot.
Vitamin E comes mainly from vegetable oils, nuts and seeds, not from carrot.
Step 4: Final conclusion.
Since carrot is rich in beta carotene, which the body converts into Vitamin A, the correct answer is Vitamin A.
\[ \boxed{\text{Vitamin A}} \]