题目2单选题
线坐标为(1,2,1)的直线的齐次方程为( )A. <img src="https://tihai-oss-cloud.itihey.com/img/e5af353d91851ba9880ac8201aa78ae4.webp">B. <img src="https://tihai-oss-cloud.itihey.com/img/acf05b6ad5d03d3da4d4bb6378b36279.webp">C. <img src="https://tihai-oss-cloud.itihey.com/img/ddcd9ef7a3d2774cb3d81d5a94c87854.webp">D. <img src="https://tihai-oss-cloud.itihey.com/img/1bd6fc6ac4bee3c9c2c65dc47555942b.webp">