Which of the following technique is meant for the preparation of curved canal?

Modified double flare technique:   Meant for curved canal. In this, preparation was commenced in the coronal part of the root canal. A #40 Flex R file was instrumented in the straight part of the canal, using the balanced force technique. Sequentially, larger sizes of files were used to instrument the straight part of the canal using the balanced force technique and  the coronal 4 to 5 mm of the root canal was instrumented with Gates-Glidden drills. A #20 Flex R file was taken to the working length and the canal prepared using the balanced force technique by sequential use of files. Preparation at the working length was continued until clean dentin was removed, the master apical varying between #40 and 45. Textbook of Endodontics Nisha GARG 3rd ED