What type of volcano will most likely form when intermittent eruptions of different intensities take place over a long period of time and layers of ash and lava pile up?

The correct answer is a cinder cone volcano

These volcanoes are formed when tephra, which is the name for all matter that leaves the volcano regardless of size or composition, falls on the ground and accumulates and builds it up. The higher they are the steeper they are because the heavy weight materials fall near the top and it grows in height, while the lower weight flies towards the bottom.