Read the following statements and choose the correct ones.
A. Light always inhibits seed germination.
B. Optimum temperature for seed germination is 10-15degC.
C. Photoperiodism and vernalisation both are main phenomenon involved in flowering.
D. Vernalisation can shortens the period between germination and flowering.

Options

A. A and B
B. B and C
C. C and D
D. A and D

Answer

To solve the question, we need to evaluate each statement regarding seed germination and flowering processes. Let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement A: Light always inhibits seed germination.**
- This statement is **incorrect**. While light can influence germination, it does not always inhibit it. In fact, for many seeds, light is a necessary factor that stimulates germination. Therefore, this statement is not correct.

2. **Statement B: Optimum temperature for seed germination is 10-15°C.**
- This statement is also **incorrect**. The optimum temperature for most seeds to germinate typically ranges from **15-30°C**. While some seeds may germinate at lower temperatures, the general range for optimal germination is higher than what is stated.

3. **Statement C: Photoperiodism and vernalization both are main phenomena involved in flowering.**
- This statement is **correct**. Photoperiodism refers to the response of plants to the length of day and night, which influences flowering. Vernalization is the process where exposure to a prolonged period of cold promotes flowering. Both processes are crucial for the flowering of many plants.

4. **Statement D: Vernalization can shorten the period between germination and flowering.**
- This statement is **correct**. Vernalization helps to induce flowering after a period of cold exposure, effectively shortening the time between germination and flowering in certain plants. This is an important aspect of plant development.

### Conclusion:
The correct statements are **C and D**. Therefore, the answer to the question is that statements C and D are correct.