B. Checkbox The most suitable type of custom field for tracking whether an employee wears glasses or not on an Employee record in NetSuite is a **Checkbox**. This type of field allows for a simple yes/no or true/false selection, which is ideal for a straightforward attribute like this. When the checkbox is checked, it indicates that the employee wears glasses; if unchecked, it means they do not. This binary option makes it easy to filter and report on employees who wear glasses, without the need for more complex data entry like a drop-down list or radio buttons.