A VTS operator observes two power-driven vessels, Vessel A and Vessel B, on a collision course in open water. Vessel A is on Vessel B's port bow, meaning Vessel B has Vessel A on its own starboard side. Neither vessel is constrained in any way. According to the International Regulations for Preventing Collisions at Sea (COLREGs), which vessel is the 'give-way' vessel?

1. Both vessels are required to alter course to starboard.
2. Vessel A is the 'stand-on' vessel and should maintain its course and speed.
3. Vessel B is the 'give-way' vessel and should take early and substantial action to keep well clear.
4. Vessel A is the 'give-way' vessel and should expect Vessel B to maintain course and speed.