题目9单选题
下列凸轮机构中,图( )所画的压力角是正确的.A. <img src="https://tihai-oss-cloud.itihey.com/img/1b2fad770a29c04ab236df320fadcaea.jpg">B. <img src="https://tihai-oss-cloud.itihey.com/img/74b10908efbb214f598ebfbcc5ce47de.jpg">C. <img src="https://tihai-oss-cloud.itihey.com/img/f5a072cf63db884759240b38d4276825.jpg">