What kind of stain is most commonly used to visualize the capsule of cryptococcus?
gram stain
simple stain
negative stain
fluorescent stain

negative stain

Explanation:

Negative staining is one of the staining procedures that stains the background of the sample dark to visualize the unstained specimen. Capsule staining in Cryptococcus follows the process of negative staining in which the background of the cells of Cryptococcus is stained blue-black with help of India ink.  

The particles of the stain are unable to penetrate the cells and/or capsule leaving them unstained. Here, the cells of Cryptococcus can be stained using a counter-stain to better visualize the unstained capsules.