Final answer:
The correct answer is 'b. Average lead-to-customer rate'. It is a business metric that measures how many leads convert into paying customers, reflecting the efficiency of the company's sales funnel.
Step-by-step explanation:
The number of leads you generate that actually become paying customers is known as your average lead-to-customer rate. This metric measures the effectiveness of your lead generation and conversion processes by indicating the proportion of leads that result in sales. A higher average lead-to-customer rate suggests a more efficient sales funnel where a greater percentage of interested prospects are successfully converted into customers, thereby contributing to the company's revenue.