The capsule of cryptococcus neoformans in a CSF sample is best seen by -
Cryptococcus is the capsulated yeast.
Among the given staining techniques, India ink preparation is the best staining technique used for demonstration of capsule (negative staining) - sensitivity of the technique: 60–75%.

Other capsular staining techniques are:

10% Nigrosin staining
Modified India ink preparation with 2% chromium mercury
Alcian blue staining

Methanamine silver and Periodic acid- Schiff – used for tissue sample.
Sensitivity of various diagnostic tests- Harrison 18/e p1652

Cryptococcal antigen detection in CSF—90%
Blood culture: 10—30% in non-HIV patients and 60% in HIV patients
Sputum culture: 10%
Sputum antigen detection: 30%
Gram stain
India ink preparation
Giemsa stain
Methenamine-silver stain