单项选择题

A.乙烷中C−H键,k=5.9×105达因∙cm-1
B.乙炔中C−H键,k=5.9×105达因∙cm-1
C.乙烷中C−C键,k=4.5×105达因∙cm-1
D.乙醛中C=O键,k=12.3×105达因∙cm-1