He was either the get-away driver or had to steal, carry and load the stuff.
Two persons are required to steal a lot of stuff.
The council the defence may argue that he was a Innocent by-driver or only an Innocent onlooker when the dumb B had to steal the stuff. (imagine not capable of driving)
I would arrest DEF as well. in case somebody lied about only 3 persons.
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Never do today what you can put of until tomorrow - Student motto
A may be a driver who is unnaware a crime has taken place. Just because A has been invited to be an accomplice C may have lied to him without telling him what the real reason is.
If A was not involved, C was involved, so either:
A will have either have committed the robbery on his own or with C; or
A will have been invited to by C to be an accomplice and will have refused to take part (A might even have believed that the crime would not take place following his refusal).
So we have no way of knowing. As with the "Hardest Logic Puzzle", the "experts" are making unwarranted assumptions. [But at least the "Hardest ..." remains soluble without those assumptions]