Measured usage represents the ability of a cloud platform to keep track of the usage of its IT resources by cloud consumers. The __________________ mechanism can be used for the collection of billing information so that the cloud provider can charge the cloud consumer only for the IT resources actually used.

a. resource replication
b. pay-per-use monitor
c. automated scaling listener
d. multi-device broker

Statement (b) is correct because this is the cloud computing mechanism used specifically for what is described in the question text.