最可能的疾病为

A．急性左下肢动脉栓塞

B．左下肢深静脉血栓形成

C．左下肢深静脉瓣膜功能不全

D．血栓闭塞性脉管炎

E．动脉瘤

An analyst does research about cash flow classification. The initial cash payment for an equity security is considered an investment cash flow. The security is least likely to be classified as:（）

A. held for trading.

B. held to maturity.

C. available for sale.