What are the two ways to fire without an FDC?

The correct answer identifies the two methods of firing mortars without relying on a Fire Direction Center (FDC). Direct Lay involves positioning the mortar tube to fire directly at the target without calculating a firing solution through complex computations typical of indirect fire missions. It relies on the gunner visually aligning the sight with the target. Direct Alignment is a similar technique where the mortar crew aligns their equipment to the target and may adjust their sighting based on visual cues and target location.

Using these methods, mortar crews can effectively engage targets without the traditional support that an FDC provides, which normally coordinates fire missions using data and calculations. This is particularly advantageous in rapid or changing combat situations where immediate fire support is necessary.