Which of the following are common infill patterns used in 3D printing?

B is the correct answer because grid, honeycomb, and triangle are all well-established infill patterns commonly utilized in 3D printing.

The grid pattern consists of evenly spaced lines in both directions, creating a sturdy lattice that provides good support while minimizing material use. The honeycomb pattern is known for its efficiency in providing strength and stability while also using less material compared to solid fills. The triangle infill, characterized by its geometric structure, offers a balance of density and support, often being used for ensuring strength in specific applications.

These patterns are favored for their balance of structural integrity and material efficiency, making them suitable for various 3D printing applications.