Kasundi, a staple in Bengali cuisine, is a piquant paste predominantly featuring mustard seeds. It typically serves as a condiment for fish and other culinary preparations.
- While coriander seeds feature in numerous spice mixes, they do not form the base of Kasundi.
- Fenugreek seeds, known for their characteristic taste, are integral to many Indian dishes but are not the primary component of Kasundi.
- Nutmeg, a sweet spice, is not a principal ingredient in Kasundi.
Consequently, Mustard seeds are identified as the correct answer.