Alaya's Secret is a chain of beauty salons, where part of the employees' monthly leave time is granted depending on customer feedback. Two days of leave are granted based on performance, and the remaining three days are granted based on customers' feedback on the quality of service. In this case, Alaya's Secret is committed to $\_\_\_\_\_.$

a$.$

line$-$flow production

b$.$

total quality management

c$.$

internal service quality

d$.$

implementing a just$-$in$-$time program