Robert Hits His Kindergarten Teacher's Arm to Get His Attention

Robert hits his kindergarten teacher's arm to get his attention, even when the teacher is busy with other children. The teacher has documented that this occurs about eight times every day. This child's challenging behavior is most likely rooted in:

A) simply not knowing how to get the teacher's attention appropriately
B) having to do too many workbook pages
C) having a fully developed occipital connection
D) a lack of sleep
E) both B and C