Final answer:
The correct KPI from the options provided is C. The percentage of help desk calls answered in the first minute, as it is a measurable value that can evaluate customer service efficiency. Additionally, productivity can be measured using various other metrics, such as output quality and customer satisfaction.
Step-by-step explanation:
Key performance indicators (KPIs) are quantifiable measures that businesses use to assess their success in achieving key business objectives. Among the provided options, C. The percentage of help desk calls answered in the first minute is a good example of a KPI because it is a specific, quantifiable metric that can be measured over time to assess improvements in customer service efficiency.
Productivity can be measured in other ways than the amount produced per hour of work. Some alternative measures of productivity include the quality of the output, customer satisfaction levels, turnover rates, and efficiency improvements such as reduced waste or lower energy consumption.