What is the strategy currently used in gene therapy ( ) ( 2013 )目前，基因治疗主要采用的方法是
选项：

A:Recombining the patient's genes 对患者缺陷基因进行重组
B: Promoting DNA synthesis in patients 提高患者的DNA合成能力
C: Correcting the DNA repair enzymes in patients 调整患者DNA修复的酶类
D: Injecting cells expressing the target gene into the patients.将表达目的基因的细胞输入患者体内