An Experimental Psychology Lab Student Is Having Difficulty Making a Number

An experimental psychology lab student is having difficulty making a number of decisions such as identifying the variables to use in the experiment and the type of research participants to use. This difficulty could be because the student

A) did not have the psychology null hypothesis.
B) did not have a research problem that was specific enough.
C) did not state the research problem as a question.
D) forgot to write a scientific hypothesis.