Please explain in detail! I apologize for posting two questions so at the very least do the first one! Thank you!

For questions from 12 to 14, assume the following situation. Sue invested in Snap chat stock. The current stock price is $20 per share. She will close her position in Snapchat when the stock price becomes $21 or S15 whichever comes first. Assume the Snapchat stock price is a martingale. 12. What is her expected return when she closes her position? 1) $40k 2) $20 3) $2,000 4) 0% 5) 5% 13. What is the probability of having 5% net return? l) 17.67% 2) 35.56% 3) 51.34% 4) 75.56% 5) 83.33%