Ans is B Perfective maintenance
There are four types of maintenance, namely, corrective, adaptive, perfective, and preventive.
Corrective maintenance is concerned with fixing errors that are observed when the software is in use.
Adaptive maintenance is concerned with the change in the software that takes place to make the software adaptable to new environment such as to run the software on a new operating system.
Perfective maintenance is concerned with the change in the software that occurs while adding new functionalities in the software.
Preventive maintenance involves implementing changes to prevent the occurrence of errors. The distribution of types of maintenance by type and by percentage of time consumed.
