Citing the recent increase in earnings by several computer companies, economists feel that a cycle has begun in which personal computer users, especially corporate consumers, are replacing their PC's with more powerful models.

• Aa cycle has begun in which personal computer users  
• Ba cycle for personal computer users has begun in which they  
• Cthere is a cycle beginning for personal computer users  
• Dit is the beginning of a cycle for personal computer users  
• Epersonal computer users are in the beginning of a cycle when they