It Has Been Hypothesized That Some Mental Resources (E

It has been hypothesized that some mental resources (e.g., the response selector) are unitary and therefore are not divisible. If two tasks both require one of these unitary resources, divided attention between these two tasks will

A) not be possible.
B) be possible only by means of sharing of the resource between the two tasks.
C) be possible only if one of the tasks requires more resources than the other.
D) be possible only if the two tasks make matched demands of the resource.