The following three kinds of leaves were exposed to light :
I. Variegated leaf
II. Green leaves partially covered with black paper
III. Green leaf
Presence of starch was seen in

Options

A. Only in the green leaves
B. Both green and variegated leaves
C. All the leaves in which green parts exposed to light
D. Only variegated leaf

Answer

To determine the presence of starch in the three kinds of leaves exposed to light, we need to understand the process of photosynthesis and how it relates to starch production.

### Step-by-Step Solution:

1. **Understanding Photosynthesis**:
- Photosynthesis is the process by which green plants use sunlight to synthesize foods with the help of chlorophyll. The primary product of photosynthesis is glucose, which can be converted into starch for storage.

2. **Analyzing the Leaves**:
- **Variegated Leaf**: This type of leaf has both green (chlorophyll-containing) and non-green (chlorophyll-deficient) areas. Only the green parts can perform photosynthesis and produce starch.
- **Green Leaves Partially Covered with Black Paper**: The covered parts will not receive light, thus cannot perform photosynthesis. Only the exposed green parts will be able to produce starch.
- **Green Leaf**: This leaf is fully green and can perform photosynthesis throughout its surface, producing starch in all areas.

3. **Conclusion on Starch Presence**:
- Starch will be present in the green parts of the variegated leaf, in the exposed parts of the green leaves covered with black paper, and throughout the fully green leaf. Therefore, starch will be present in all the leaves where the green parts are exposed to light.

4. **Final Answer**:
- The correct option is: **All the leaves in which green parts are exposed to light**.