Whichofthefollowingstatementsabout"shortselling"isTRUE（）

A. A short position may be hedged by purchasing put options.

B. Short sellers may be subject to margin calls if the stock price increases.

C. Stocks that pay large dividends should be sold short before the ex-dividend date and bought afterward to take advantage of the large price decline in a short time period.

已知如图，△ABC中，AB=AC，D是AB的中点，DE⊥AB交AC于E，

（1）若BE平分∠ABC，求∠A的度数．

（2）若△ABC的周长为10，△BCE的周长为6，求BC的长度．