Given below are four matchings of an animal and its kind of respiratory organ.
`{:("A. Silver fish - Trachea"),("B. Scorpion - Book lung"),("C. Sea squirt - Pharyngeal gill slits"),("D. Dolphin - Skin"):}`
The correct matchings are

Options

A. (a) and (d)
B. (a),(b) and (c )
C. (b) and (d)
D. ( c) and (d)

Answer

To determine the correct matchings of animals and their respiratory organs, we can analyze each option one by one.

### Step-by-Step Solution:

1. **Silver Fish - Trachea**:
- Silverfish are classified as insects and possess a respiratory system that includes tracheae. Therefore, this matching is **correct**.

2. **Scorpion - Book Lung**:
- Scorpions are arachnids and they have specialized respiratory organs known as book lungs. Thus, this matching is also **correct**.

3. **Sea Squirt - Pharyngeal Gill Slits**:
- Sea squirts (or tunicates) have pharyngeal gill slits as part of their respiratory system. Hence, this matching is **correct** as well.

4. **Dolphin - Skin**:
- Dolphins are mammals and they possess lungs for respiration, not skin. Therefore, this matching is **incorrect**.

### Conclusion:
The correct matchings are:
- A. Silver Fish - Trachea (Correct)
- B. Scorpion - Book Lung (Correct)
- C. Sea Squirt - Pharyngeal Gill Slits (Correct)
- D. Dolphin - Skin (Incorrect)

Thus, the correct answer is options A, B, and C.