问题如下：
Based on Exhibit 1, Strategy 5 offers:
选项：
A.unlimited upside.
a maximum profit of €2.48 per share.
protection against losses if QWY’s share price falls below €28.14.
解释：
B is correct.
Strategy 5 describes a collar, which is a combination of a long position in shares, a long put option, and a short call option. Strategy 5 would require Nuñes to buy 100 QWY shares at the current market price of €28.49 per share. In addition, she would purchase a QWY April €24.00 strike put option contract for €0.35 per share and collect €0.32 per share from writing a QWY April €31.00 strike call option. The collar offers protection against losses on the shares below the put strike price of €24.00 per share, but it also limits upside to the call strike price of €31.00 per share. Thus, the maximum gain on the trade, which occurs at prices of €31.00 per share or higher, is calculated as (X2 – S0) – p0 + c0, or (€31.00 – €28.49) – €0.35 + €0.32 = €2.48 per share.
请问collar与bull spread的区别是什么?
