Investment bankers perform the following role ___________.

Answer: Option D

Option A: market new stock and bond issues for firms - Investment bankers act like a bridge between companies that need to raise money and investors who want to invest. They help companies sell (or market) new stocks (shares of ownership) and bonds (loans to the company) to the public. Think of them as the company's sales team for raising capital.

Option B: provide advice to the firms as to market conditions, price, etc - Investment bankers are experts in the financial markets. They give companies advice on things like:
    * Market Conditions: Is it a good time to sell stocks or bonds? What are investors looking for right now?
    * Price: How much should we charge for each share of stock or bond? (They want to get the best price for the company!)

Option C: design securities with desirable properties - Investment bankers don't just sell existing stocks and bonds. They can also help companies create (or design) new types of stocks or bonds with specific features (desirable properties) that might attract investors. For example, they might create a bond that pays a higher interest rate or a stock that pays a dividend.

Since investment bankers perform all these roles, the answer is Option D: all of the above.