Which of the following is a common revenue stream for sports facilities?

Concessions are indeed a common revenue stream for sports facilities. These sales often include food, beverages, merchandise, and other items sold during events. Concession stands can generate significant revenue, particularly during large events where many attendees are present. The high volume of customers combined with the markup on food and drink items leads to a profitable income source for the facility.

Other options such as training fees and equipment leasing are more specific and not typically the main revenue sources for most sports facilities. Training fees might be relevant for training facilities but are not a standard revenue stream for large venues that host events. Player salaries are expenses rather than revenue streams, as they represent costs incurred by the facility or team rather than income generated.