( a ) are present on the inside wall of seminiferous tubules multiply by meiotic division and remain constant in numbers

( b ) are present on the inside wall of seminiferous tubules multiply by mitotic division and remain constant in numbers

( c ) are present on the inside wall of seminiferous tubules multiply by meiotic division and increase in numbers

( d ) are present on the inside wall of seminiferous tubules multiply by mitotic division and increase in numbers