Tamika hypothesizes that women are more helpful than men, and she decides to conduct an experiment to test her hypothesis. During lunchtime, she goes to the crowded food court and deliberately drops her folder containing papers. She then notes whether the person standing closest to her helps her pick up her papers and whether the person is male or female. What is the operational definition of "helpful" in Tamika's study?
A. the gender of the person
B. the person asking Tamika if she dropped her notebook
C. establishing eye contact
D. making an effort to gather the papers