When the crust is compressed, it typically results in which of the following rock formations?

The formation of anticlines and synclines is a common result of crustal compression. This process occurs when tectonic forces push the Earth's crust together, causing it to fold. An anticline is an upward arching fold, while a syncline is a downward trough-like fold. The creation of these structures is a direct result of the intense pressure exerted on the crust, leading to bending and folding rather than breaking.

In the context of the other options, while faults can form as a result of crustal tension or compression, they are not the primary feature associated with simple compression; instead, they usually represent fractures or discontinuities in the rock where movement has occurred. Volcanoes are primarily formed by melting of rock leading to magma movement, not directly due to compression. Earthquakes can occur as a result of both fault activity and crustal movement, but they are a result of the release of energy from accumulated stress rather than a direct formation feature like an anticline or syncline. Thus, the answer focusing on the folding of rocks under compression reflects the geological processes involved accurately.