When performing the oxidase test, which technique can be used?

In the oxidase test, the primary goal is to determine the presence of cytochrome c oxidase in bacteria, which is an enzyme involved in the electron transport chain. The options presented for performing the test illustrate different techniques that all serve the same purpose.

Using a drop of reagent directly on a colony is a straightforward method that yields immediate results, making it a viable option. Rubbing the colony onto a filter paper strip and then adding the reagent is another technique that allows for the reaction to be easily observed, as the color change can be clearly noted against the white background of the paper. Additionally, rubbing the colony on filter paper that contains the reagent can enhance the exposure of the bacteria to the reagent, promoting a more robust reaction.

Each of these techniques is effective for performing the oxidase test, showcasing the flexibility in methodology while achieving the same end result—detecting the presence of cytochrome c oxidase. Therefore, since all the provided methods are valid for this test, the correct answer encompasses all techniques as acceptable options.