Which of these errors are random? a. trial time is recorded with a watch that is a half second off each minute. b. the door to a dark room is opened while an x-ray is being developed. c. a balance was not zeroed before being used to measure the mass of an object. d. a student misreads the temperature on a thermometer. e. the use of a cell phone interferes with the radio frequency of an electronic device. check all that apply.