Which is not an example of a performer-control error?

	a.	Staff did not collect rate data during sessions on Tuesday because the electronic data collection system was down.
	b.	Staff ran three times the average number of trials on a day they worked three extra sessions in the clinic.
	c.	Staff did not review session notes on arrival to session because the session notes were unavailable.
	d.	Staff arrived to work on time five days in a row.