The evaluation apprehension explanation for the source of arousal that produces social facilitation posits that leads to increased arousal-

the presence of others who might judge us                          

Explanation:

In psychology, the concept of social facilitation was first introduced by one of the famous psychologist named Norman Triplett during 1898 and later on during 1920, Floyd Allport termed it as social facilitation.

The phenomenon of social facilitation states that a person tends to perform better on specific tasks when he or she is surrounded by another person rather than alone.

In reference to the question above, the concept of social facilitation signifies "the presence of others who might judge us" can increase arousal.

the answer is d.index