Professor Bertolin Wolfcheng wanted to study the cause for thousands of people from Hong Kong moving to Vancouver, British Columbia. In order to establish temporal order in his causal argument he must show which of the following:

Select one:

a.There is a correlation between events in Hong Kong and a decision to move.

b.Events occurred in Hong Kong before people moved to Vancouver.

c.A fear for the future of Hong Kong and no other reason caused the move to Vancouver.

d.All of the above.