A Few Years Ago Anti-Trust Proceedings (Proceedings for Uncompetitive Conduct)

A few years ago anti-trust proceedings (proceedings for uncompetitive conduct) were brought against Microsoft in the USA.The company was alleged to have abused its monopoly in the desktop operating systems market.The Court decided that:

A) there was ample and adequate scope for any potential competitor to develop a viable alternative to Windows
B) there was a 'barrier to entry' that made it prohibitively expensive for a potential competitor to develop into a viable alternative to Windows.
C) Microsoft had a healthy monopoly that delivered an effective and cost efficient product to consumers.
D) it was expensive but viable for potential competitors to develop an alternative to Windows and therefore the market was sufficiently competitive.