Hello Aaradhana joshi , 

No , you don't have to remove all the interface setting configured in Task 2 , while performing Task 3 (A) . Because from R3 , you are sending individual routes and from R4 sending summary routes , so interface characteristics doesn't effect this task . And in task 3 , we are not  manipulating the path .   But as given in guidelines for the task is recommended that you have to cleared previous task configuration to perform next-one . In case of Task 4 , you have to remove previous task configuration . 

Have a nice day .