[单选题]
The diagram shows how RNA is transcribed fr+*wh4 t vfz4xystv :0n8x8j iqom DNA. What structuresi 5it1c7cpxq60:cqj )bwckfd1b k.v8 are indicated by tk1pcb kftixbq.iv)dw1:75c0q6 c j8 che labels X, Y, and Z?
A. $X$ is 5’ end of DNA;Y is 3’ end of RNA; Z is RNA polymerase
B. $X$ is 5’ end of DNA;Y is 3’ end of RNA; Z is DNA ligase
C. $X$ is 3’ end of DNA;Y is 5’ end of RNA; Z is RNA polymerase
D. $X$ is 3’ end of DNA;Y is 5’ end of RNA; Z is DNA polymerase