Please show all working out in details. Many thanks.

Suppose a firm offers an equity-linked security. The face value is $1 million and its payoff is based on any appreciation in an equity index currently at 855.50 . It has determined that of the $1 million raised, it can structure the option component so that its value is $135,000. Currently an at-the-money call option is worth $125. What percentage of the gain in the index can it offer? 50%8.23%100%92%