Pearl is formed when a foreign substance gets trapped between A of B
(a) A- Shell and mantle B - Pila
(b) A- Nacreous and prismatic layer B-Pinctada
(c) A - Shell and mantle B Pinctada
(d) A- Nacreous and prismatic layer B- Ostrea

Options

A. A- Shell and mantle B - Pila
B. A- Nacreous and prismatic layer B-Pinctada
C. A - Shell and mantle B Pinctada
D. A- Nacreous and prismatic layer B- Ostrea

Answer

To solve the question regarding how pearls are formed, we need to analyze the options provided and understand the process of pearl formation.

### Step-by-Step Solution:

1. **Understanding Pearl Formation**: Pearls are formed when a foreign substance, such as a grain of sand or a parasite, gets trapped inside a mollusk. The mollusk then secretes layers of nacre (mother-of-pearl) around this foreign object.

2. **Identifying Components**: The question asks for the components involved in pearl formation:
- **A** refers to the layers or parts of the mollusk where the pearl forms.
- **B** refers to the specific species of mollusk involved in the pearl formation.

3. **Analyzing the Options**:
- **Option (a)**: A - Shell and mantle, B - Pila
- This option mentions "Pila," which is not commonly associated with pearl production.
- **Option (b)**: A - Nacreous and prismatic layer, B - Pinctada
- This option describes the layers but incorrectly identifies the species.
- **Option (c)**: A - Shell and mantle, B - Pinctada
- This option correctly identifies both the layers (shell and mantle) and the species (Pinctada) known for pearl production.
- **Option (d)**: A - Nacreous and prismatic layer, B - Ostrea
- This option mentions "Ostrea," which is not the primary species used for pearl production.

4. **Selecting the Correct Answer**: Based on the analysis, Option (c) is the only one that correctly states that pearls are formed between the shell and mantle of the mollusk Pinctada.

### Final Answer:
(c) A - Shell and mantle, B - Pinctada