Possible sources of contamination of the nutrient medium in plant tissue culture are :

A. the medium itself
B. the culture vessel
C. the explant
D. the environment of the transfer area
E. the operator

Choose the most appropriate answer from the options given below:

A

A, E only

B

B, C only

C

A, B, C, D only

D

A, B, C, D, E only