The skid in a stylus type roughness measuring instrument is used to provide ............ A .............. and define ................... B .............. geometrical profile of the surface.

$$A.$$ support / datum
$$B.$$ micro / macro

A shaft of diameter $${20^{\matrix{ { + 0.05} \cr { - 0.15} \cr } }}$$ and a hole of diameter $${20^{\matrix{ { + 0.20} \cr { + 0.10} \cr } }}\,\,mm$$ when assembled would yield.

To obtain dimension of $$61.18$$ $$mm$$ using slip gages, the most appropriate combination is

The fit on a hole-shaft pair system is specified as $$H7$$-$$s6$$. The type of fit is