Which one of the following is not a synthetic abrasive material

The flanks of teeth of rack-type gear cutter used for cutting involute gear profiles are:

The purpose of helical grooves in a twist drill is to
$$1.$$ Improve the stiffness
$$2.$$ Save a tool material
$$3.$$ Provide space for chip removal
$$4.$$ Provide rake angle for the cutting edge

Select the correct answer suing the codes given below

Match list - $${\rm I}$$ (machine tool) with list - $${\rm I}$$$${\rm I}$$ (machine tool part)