The correct answer is Clotrimazole.

- Clotrimazole is an azole antifungal agent that works by inhibiting the synthesis of ergosterol, which is an essential component of the fungal cell membrane.
- Ergosterol plays a crucial role in maintaining the structure and integrity of the fungal cell membrane.
- By inhibiting the enzyme lanosterol 14-α-demethylase, clotrimazole disrupts ergosterol production, leading to increased membrane permeability and ultimately fungal cell death.

In contrast:

- Flucytosine inhibits fungal DNA and RNA synthesis by being converted into 5-fluorouracil inside fungal cells.

- Griseofulvin interferes with microtubule function and inhibits fungal mitosis.

- Amphotericin B binds directly to ergosterol in the fungal cell membrane, creating pores that cause leakage of cellular contents but does not inhibit ergosterol synthesis.

Thus, among the options given, only Clotrimazole acts by inhibiting ergosterol synthesis.

Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 13th Edition, Volume 2, Chapter 46: Antifungal Agents