Major computer vendors stopped using proprietary motherboard designs for their computers (true/false)?

Major computer vendors stopped using proprietary motherboard designs for their computers is False.

Explanation:

Most Vendor systems, similar to Dell, HP, Sony, IBM, and so forth utilize proprietary motherboard, extraordinarily made to fit their systems, by motherboard vendors. Proprietary Designs Motherboards that are not one of the business standard structure factors, for example, AT/Baby-AT, NLX, or any of the ATX groups, are considered restrictive or semi-exclusive.

The most widely recognized structure factor is ATX, which developed to smaller than usual ATX, nano-ATX, pico-ATX, and further. An alternate kind of structure factor, and littler than the ATX is the ITX, which is altogether littler than the smaller scale ATX. The ITX structure factor can likewise be found as nano-ITX, pico-ITX, versatile ITX, and the sky is the limit from there.

system programmer option d is correct

because an operating system is software that manages computer hardware and system resources.