The parameter to be increased in order to increase the angular magnification of a simple microscope is

power of the lens

The correct answer is Option (3) → power of the lens

The angular magnification of a simple microscope is $M = \frac{25 \, \text{cm}}{f}$

To increase $M$, the focal length $f$ of the lens should be decreased, i.e., use a lens with higher power.

Final Answer: power of the lens