ET0=0；这个语句表示（）

orating sales trend. Specifically, the number of customers is stable at 1500 but they are purchasing less each year. She orders her staff to search for causes of the downward trend by surveying all 1500 industrial customers. One question on the survey asked the customers ‘How many people does your company employ: （） 1001+’. The measurement level for this question is ___________________.A．nominal levelB．ordinal levelC．interval levelD．ratio level