(A) : An ammeter is connected in series in the circuit.
(R) : An ammeter is a high resistance galvanometer.

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. 'A' is true and 'R' is false
D. 'A' is false and 'R' is false

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states: "An ammeter is connected in series in the circuit."
- This is true because an ammeter is designed to measure the current flowing through a circuit. When connected in series, the same current flows through the ammeter as through the rest of the circuit components.

2. **Understanding the Reason (R)**:
- The reason states: "An ammeter is a high resistance galvanometer."
- This statement is false. An ammeter is actually designed to have a low resistance. If it had high resistance, it would impede the flow of current, leading to inaccurate measurements.

3. **Conclusion**:
- Since the assertion is true and the reason is false, we conclude that the correct answer is that the assertion is true, but the reason does not correctly explain the assertion.

### Final Answer:
- Assertion (A) is true.
- Reason (R) is false.