Answer:
What crime Mark and Jack have committed? Criminal conspiracy.
Step-by-step explanation:
In order to criminal conspiracy exists, there should always be an agreement between two or more people where they plan to commit an unlawful act.
There are no formalities in this agreement, it just takes one person to convince another and start planning all the details.
In this example, Mark and Jack did not get to rob the bank but just for the intention, they are arrested.