Corporate bonds (Option B) have the most developed ESG integration, primarily due to:

Corporate ESG disclosures that provide granular data on sustainability risks.

Sustainability-linked bonds (SLBs) and green bonds, which have specific ESG performance targets.

ESG credit ratings from agencies like S&P, Moody’s, and MSCI ESG Ratings.

Option A (Agency bonds) (issued by government-backed institutions) have some ESG integration, but not as advanced as corporate bonds.

Option C (Government bonds) have increasing ESG focus (e.g., sovereign green bonds) but lack standardized ESG metrics.