Match List-I with List-II and select the correct answer using the options given below the lists:

List-I (Instruments)	List-II (Measurement in which the instrument is used)
a. Lock-in amplifier	1. Patient monitoring
b. Sampling oscilloscope	2. Overcoming ground loop problem
c. Isolation amplifier	3. Phase difference between two signals
d. Strip-chart recorder	4. Signal recovery form noise
	5. Observing very high frequency signals

A. a-1, b-3, c-5, d-4

B. a-2, b-1, c-3, d-4

C. a-4, b-5, c-2, d-1

D. a-3, b-4, c-1, d-2

Answer: Option C