Dr Ewell, a Developmental Psychologist, Is Planning on Conducting a Study

Dr. Ewell, a developmental psychologist, is planning on conducting a study that involves watching children play together to determine how sharing behavior occurs in same-sex friend pairs compared to opposite-sex friend pairs.
Imagine that Dr. Ewell wants to videotape the children interacting in the park. Which of the following is true?

A) He will likely need to get permission to videotape the children prior to doing so.
B) If he uses hidden cameras, he does not need to tell the participants they have been videotaped.
C) He will be unable to use videotape because he is studying children.
D) He can use the videotapes regardless of whether the adult objects as long as the child agrees.