One of the Disadvantages of Proprietary Software Is That

One of the disadvantages of proprietary software is that:

A) it is hard to control results even if one is involved in the development of software.
B) it can take a long time and significant resources to develop the required software features.
C) it does not allow modification of features?that one might need to counteract an initiative by competitors.
D) it is difficult to achieve what is required in terms of features and reports.