Can you please help me with the following question. I don't know what formula to use because there is no stock price or strike price mentioned in the problem.

A new Equity-Linked Note developed by a bank guarantees that investors will receive a return during a 6-month period that is the greater of (a) zero or (b) 40% of the return of the S&P500 market index.

Describe the payoff of this instrument in terms of the S&P500 index underlying, any options on it and riskless bonds? Currently the risk-free rate is at 8% per annum, the dividend yield on the S&P500 index is 3% per annum, and the volatility of the index is 25% per annum. Is the product a fair deal for the investor?