Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Comparing option data between yahoo finance and CBOE for SPY options
The CBOE site, as well as some other sites and trading platforms, will show the bid/ask and statistics for that option at each individual options exchange, in addition to statistics and the best bid/offer across all exchanges. cboe.com: Delayed Quote Help lists what the single-letter codes mean. A is for the AMEX options exchange, B is for BOX, X is for PHLX, etc.