Place the following in the order that they occur during transcription initiation: 1 - formation of open complex; 2 - formation of closed complex; 3 promoter clearance; 4 - synthesis of about 10 nucleotides (3.0分) A. 1, 2, 3, 4 B. 2, 1, 4, 3 C. 2, 1, 3, 4 D. 3, 1, 2, 4 E. 3, 2, 1, 4