Which definition best expresses the meaning of the adverb 'solely'?

• A. Principally
• B. In addition to others
• C. Alone; not involving anyone or anything else
• D. Exclusively

Answer: (D)

Solely is about exclusivity: it means only that one thing is true or involved, with nothing else included. The best choice is exclusively because it conveys the same sense of restricting to a single element and excluding all others. For example, “The policy applies solely to urban areas” means the policy applies only to urban areas, with no extension to other areas. In contrast, principally means the main factor but allows others; in addition to others suggests being alongside other factors; alone can imply being by oneself rather than restricting to one factor.