You are responsible for the reliability of a high-volume enterprise application. A large number of users report that an important subset of the application`s functionality `" a data intensive reporting feature `" is consistently failing with an HTTP 500 error. When you investigate your application`s dashboards, you notice a strong correlation between the failures and a metric that represents the size of an internal queue used for generating reports. You trace the failures to a reporting backend that is experiencing high I/O wait times. You quickly fix the issue by resizing the backend`s persistent disk (PD). How you need to create an availability Service Level Indicator (SLI) for the report generation feature. How would you define it? 

Answer options:

A. As the I/O wait times aggregated across all report generation backends
B. As the proportion of report generation requests that result in a successful response
C. As the application`s report generation queue size compared to a known-good threshold
D. As the reporting backend PD throughout capacity compared to a known-good threshold

C