Opentution Practice Questions

Dear Sir
There is a question known as Renner in your lecture notes on page 224 of the book.I don’t understand one the adjustments as follows:
Renner took meals in the fully-subsidised executive canteen; the cost for the year being £135. Another fully subsidised canteen was available for the other staff.

Why is the canteen an exempt benefit? The canteen is available only for the executives. Its not available to all staff. Its like giving the directors a privilege benefit.

Thanks