Microbial water testing can be accomplished, just like other areas of microbiology, through cultivation of various organisms by non-selective and selective agar mediums and broths. In the case of undergoing microbial water testing, Thermo Fisher contains a helpful start guide for general and selective broth and agar choices with QC ATCC strains. The following is a list of broths, mediums, and agars used:
Slanetz ad Bartley medium (Enterococcus agar), Tergitol 7-Lactose-TTC agar (enumeration of coliform recovery), Pseudomonas C-N selective agar (Cetrimide agar), Enterococcus Selective agar (BAA) Bile Aesculin Azide agar, Kanamycin Aesculin Azide selective medium, Legionella BCYE-Agar without L-cystine, Legionella GVPC selective medium, Membrane Clostridium Perfingens (mCP) agar, Tergitol-7-Lactose TCC medium contact plate, Minerals Modified Glutamate or Minerals Modified Glutamate x2 strength (Durhan tube) bottles, and nutrient agar.
Thus based off of your answer choices provided in your question the best close acceptable answer would be using nutrient agar.