Which sentence correctly uses whereby to mean 'by which'?

• A. The contract includes a clause whereby the company may terminate employees.
• B. The contract includes a clause thereby the company may terminate employees.
• C. The contract includes a clause through which the company may terminate employees.
• D. The contract includes a clause with which the company may terminate employees.

Answer: (C)

Whereby means “by which” and introduces the means or method by which something happens. In this sentence, the clause explains the way the company may terminate employees, so whereby is the natural and precise way to express that mechanism.

The other phrasing shifts the sense: using thereby would imply a consequence or result rather than the method; through which is another way to say “by which” but uses a different connector, not the one specified; with which sounds awkward here and can misdirect the meaning toward an instrument or relation rather than the method.