An investment bank assists companies involved in mergers and acquisitions (M&A) - both from the seller's side and buyer's side.

• A. Assisting companies involved in mergers and acquisitions (M&A) on both seller and buyer sides.
• B. Providing consumer loans and retail banking services.
• C. Regulating financial markets.
• D. Underwriting only sovereign debt issuances.

Answer: (A)

Investment banks play a central role in mergers and acquisitions by providing advisory and execution services to both sides of a deal. They help with valuing targets, assessing strategic fit, screening potential opportunities, structuring the transaction, coordinating due diligence, negotiating terms, and arranging financing to complete the deal. This dual involvement—supporting both sellers and buyers—defines their M&A advisory function and explains why this option is the best fit for the scenario.

Providing consumer loans and retail banking services are typical functions of consumer or commercial banks, not the primary role in M&A advisory. Regulating financial markets is the job of regulators and supervisory authorities, not investment banks. Underwriting only sovereign debt issuances is too narrow and not accurate, as investment banks underwrite a wide range of securities for various issuers, and their involvement in M&A goes beyond debt underwriting.