Final answer:
Without further context, it is not possible to provide a definitive answer to the marking guideline for media containing 'chri'. The term could be related to chromogenic indicators, and if so, the marking usually follows the specific protocols of the laboratory based on their testing system and requirements.
Step-by-step explanation:
The term 'chri' appears to be a typo or abbreviation that is not clear. Assuming you are referring to media containing a chromogenic indicator, the recommended marking would typically be dependent on the type of media and the chromogenic system utilized.
However, without additional context, it is not possible to provide a definitive answer to which marking is recommended for media containing chromogenic indicators. Laboratories typically have protocols for marking and labeling media based on the particular tests and indications they are using. The numbers provided (0, 1, 2, 3) could refer to a scoring system indicating the intensity of a reaction or presence of a particular microorganism, but without further information, this remains speculative.
It's important to refer to the specific protocol or instructions provided with the media for accurate preparation and interpretation.