Filing of return in case of change in management

In a Private Limited Company there are 2 directors in F.Y. 2018-19 - Mr A and Mr B. Mr A and Mr B resign from the Company as on 31st January 2019 and Mr. C and Mr. D are appointed as directors. In this case who is responsible to file the return for F.Y. 2018-19 - Mr A and Mr B or Mr C and Mr D? Please give reference to the appropriate Section of the Act.