Final answer:
The correct option to automatically highlight all dates in a report that are older than six months is Conditional Formatting.
Step-by-step explanation:
The correct option to automatically highlight all dates in a report that are older than six months is a) Conditional Formatting. Conditional formatting allows you to apply formatting rules to cells based on their values or other conditions. To highlight dates older than six months, you can create a conditional formatting rule that uses the formula =TODAY()-DATE(,6,). This formula calculates the date six months ago and compares it to the dates in the report.