Hand instrument which we used to make internal angles retentive grooves and preparation of cavity walls in the cavity is.. Angle former

Hand instrument which we used to make internal angles retentive grooves and preparation of cavity walls in the cavity is:
a. Angle former.***
b. Chisel
c. File
d. Enamel hatched

A special type of excavator is the angle former. It is used primarily for sharpening line angles and creating retentive features in dentin in preparation for gold restorations.
Retention grooves are placed with a No 1/2 or 1/4 bur.