In restricted visibility, a vessel which detects by radar alone the presence of another vessel shall determine if a close quarters situation is developing or risk of collision exists. If so, she shall（）.

A.sound the danger signal

B.when taking action, make only course changes

C.avoid altering course toward a vessel abaft the beam

D.All of the above

以下对I/O超级芯片的说法不正确的是 ( )

A．大多数超级I/O芯片中至少包括软盘控制器、双串行端口控制器、并行端口控制器三个部分

B．大多数超级I/O芯片为每一个端口提供一个带缓冲器的通用异步收发器UART

C．I/O芯片中的高速多模式并行端口一般有4种模式：标准(双向)、增强并行端口 (EP、增强性能端口(EC和增强并行、性能端口(ECP/EP

D．随着芯片的集成规模越来越大以及基于USB接口的外设逐渐取代标准串、并行和软驱控制器，超级I/O芯片将会在未来的主板上消失