Final answer:
The suggested salutation for Charles' letter to an unknown company contact is "To Whom It May Concern," as it is formal and appropriately generic. Therefore, the correct option is 2) To whom it may concern
Step-by-step explanation:
When Charles is sending a letter to a company without knowing a specific contact's name, the suggested salutation would be To Whom It May Concern. This salutation is both formal and generic, suitable for situations where the recipient's name or gender is unknown, and when addressing the letter to a specific title such as hiring manager or committee is not applicable. It is important to use a colon after this salutation and leave one blank line before continuing with the letter.