From the following relative amplitude vs frequency plot, identify the type of noise which the sections A, B, C and D depict.

List-I	List-II
a. Section A	1. Thermal noise
b. Section B	2. Power line pick up
c. Section C	3. Power supply (EPC) switching noise
d. Section D	4. $$\frac{1}{{\text{f}}}$$ noise

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

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

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

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

Answer: Option C