Final answer:
An increase in tax on production of personal computers would cause a decrease in supply.
Step-by-step explanation:
In the market for personal computers, a decrease in supply would be caused by businesses being required to pay a higher tax on production of personal computers. This would increase the production cost for businesses, leading to a decrease in their willingness and ability to supply personal computers. The other options mentioned in the question would not cause a decrease in supply.
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