Question

what should always be done when using hand signals?
ensure the backup alarm can be heard
maintain eye contact with the operator
stand on something at least 2 high
wear reflective gloves

Explanation:

When using hand signals, maintaining eye contact with the operator is crucial. It ensures clear communication and understanding of the signals. Backup alarms are for auditory signals, not directly related to hand - signal use. Standing on something high is not a general requirement for hand signals. While reflective gloves can enhance visibility, eye contact is a fundamental and always - required aspect for effective hand - signal communication.

Answer:

maintain eye contact with the operator