详解
该题考察固定搭配
subject to: obliged to obey sth/sb; under the authority of sth/sb 须服从某事物[某人];受某事物[某人]授权 eg. All nuclear installations are subject to international safeguards. 所有核设施都受国际保障监督。
be subjected to 使遭受,通常接消极的表达
原文想表达电话对话受到修正案的隐私保护,D选项正确
B选项subject名词有对象的意思,虽然语义通顺,但是不是地道表达
C选项subjection征服的意思,语义不通