Which TV network originally aired 'The Big Bang Theory'?

Which TV network originally aired 'The Sopranos'? Which TV network originally aired 'Game of Thrones'? Which TV network originally aired 'Mad Men'? Which TV network originally aired 'The Walking Dead'? Which TV network originally aired 'Grey's Anatomy'? Which TV network originally aired 'Cheers'? Which TV network originally aired 'I Love Lucy'? Which TV network originally aired 'M*A*S*H'?