What Are the Advantages of Using Facial Electromyography (EMG)to Assess

What are the advantages of using facial electromyography (EMG) to assess attitudes?

A) Facial EMG can detect muscular changes not observable to the naked eye.
B) Facial EMG is not influenced by the direction of attitudes.
C) Facial EMG produces one pattern of activity that can be interpreted as happiness or sadness.
D) Facial EMG is only an accurate measure of attitudes if people know their attitudes are being assessed,so it is susceptible to the same biases as self-reports.