A restaurant chain would like to measure the proportion of customers who are generally satisfied with the service provided by its staff. At the end of the meal, as the check is delivered to the table, the server asks those at the table to rate their satisfaction with the service provided as "Very Satisfied,” "Satisfied,” or "Not Satisfied.” During a one-week period, 147 customers were surveyed and 135 (93%) reported they were either Satisfied or Very Satisfied. What type of bias may be present in the survey results? This is nonresponse bias because customers may not respond to the question. This is question wording bias because the question may be misleading to some customers. This is response bias because customers may not respond truthfully to the server. This is voluntary response bias because customers can choose to be part of the sample.