Which pennant is not displayed above the national ensign ashore but can be displayed separately?

The Church Pennant is the correct answer because it is specifically designated for use by vessels to indicate that religious services are being conducted on board. According to customary maritime practice and regulations, the Church Pennant can be flown separately and is not displayed above the national ensign ashore. This distinguishes it from other flags like the State Flag and Service Flag, which are typically associated with governmental or military identification and can be displayed in conjunction with the national ensign. The Plain Flag serves as a means to signal non-military vessels or in other specific scenarios, but it still maintains a different protocol in terms of display compared to the Church Pennant. This unique function of the Church Pennant illustrates its specific context and purpose within nautical customs.