A child is sent to the school nurse because, according to his teacher, he’s constantly scratching his head. When the nurse assesses his hair and scalp, she finds evidence of lice. What did she probably see

A. Flaking of the scalp with pink, irritated skin exposed.
B. Small white spots that adhere to the hair shaft, close to the scalp.
C. Scaly, circumscribed patches on the scalp, with mild alopecia in these areas.
D. Multiple tiny pustules on the scalp with no abnormal findings on the hair shafts.

如图所示的电流表的示数是______A．