Answer: (c)

Explanation:
The International Capital Market Association (ICMA) categorizes themed debt instruments based on how the raised capital is allocated:

(a) Green Bond: The proceeds of a Green Bond are strictly earmarked to fund or refinance projects that deliver clear environmental benefits. Examples include renewable energy installations, sustainable water management, carbon capture, and green buildings.

(b) Social Bond: The proceeds of a Social Bond are exclusively used to fund projects that address targeted social issues and aim to achieve positive socio-economic outcomes. Examples include affordable housing, food security, public healthcare, and employment generation for marginalized groups.

(c) Sustainability Bond (The Answer): A Sustainability Bond is a specific debt framework where the issuer intentionally bundles both categories together. The defining operational rule is that the proceeds must be applied only to finance or refinance a combination of both environmental (green) and social projects.

(d) Sovereign Bond: A Sovereign Bond simply refers to a generic debt security issued by a national government to support overall state expenditure or manage fiscal deficits. It is defined by the credit of the sovereign issuer rather than a specific project theme.