Odissi : Kathak : Bharatnatyam — Choose the option that belongs to the same category of Indian classical dance forms as the given trio.

Introduction / Context:
Odissi, Kathak, and Bharatnatyam are Indian classical dance forms. The task is to select another classical dance form from the options and avoid folk or theatrical forms.

Given Data / Assumptions:

• Classical dances follow codified traditions (e.g., Natya Shastra).
• Options include one classical dance and several folk/theatre forms.
• We must pick the classical form.

Concept / Approach:
'Kathakali' (Kerala) is a recognized Indian classical dance form. 'Gumar' (often spelled 'Ghoomar') is folk; 'Tamasha' and 'Nautanki' are theatrical/folk performance genres. Therefore, 'Kathakali' alone preserves the classical-dance category.

Step-by-Step Solution:
1) Establish the category: Indian classical dances.2) Identify matching option: 'Kathakali'.3) Select 'Kathakali'.

Verification / Alternative check:
Classical list typically includes Bharatanatyam, Kathak, Kathakali, Odissi, Kuchipudi, Manipuri, Mohiniyattam, Sattriya; Kathakali is canonical.

Why Other Options Are Wrong:

• Gumar/Ghoomar: Folk dance.
• Tamasha/Nautanki: Folk theatre traditions.
• None of these: Incorrect since 'Kathakali' is correct.

Common Pitfalls:
Confusing popular folk forms with classical ones. Know the canonical list.

Final Answer:
Kathakali