Sterilization of tissue culture medium is done by:

The correct option is D

Autoclaving of the medium at 120°C for 15 minutes.

The correct option is D:

Explanation of the correct option:

1. The sterilization of the tissue culture medium is done by autoclaving the medium at 120^°C for 15 minutes.
2. In this method, moist heat and condensed hot air are used to kill microorganisms.

Explanation of the incorrect options:

Option A:

1. Keeping the medium at a low temperature will not sterilize the media.
2. A low temperature will prevent the degradation of media by reducing the growth of microorganisms.

Option B:

1. The use of filtering the medium through the fine sieve will not sterilize the media.
2. The filtration process is unable to kill the microorganisms in the media.

Option C:

The addition of antifungal agents will prevent the growth of fungus but it will not completely sterilize the media.

Final answer: Sterilization of tissue culture medium is done by autoclaving of the medium at 120°C for 15 minutes.