Appropriate instrument to check the flatness of slip gage is

In an engineering drawing one finds the designation of $$20G7F8.$$ The position of tolerance of the hole is indicated by

The hole $${40^{\matrix{ {0.020} \cr { + 0.000} \cr } }}$$ & shaft, $${40^{\matrix{ { + 0.010} \cr { - 0.010} \cr } }}$$ when assembled will result in