For the reaction of BH₃ and CH₃NH₂, which diagram shows the correct flow of electrons from the Lewis base to the Lewis acid?

Diagram showing electron flow from CH3NH2 to BH3 in Lewis acid-base reaction.

Diagram showing electron flow from CH3NH2 to BH3 with a negative charge on nitrogen.

Diagram showing electron flow from CH3NH2 to BH3 with a negative charge on boron.

For the reaction of BH3 and CH3NH2, which diagram shows the correct flow of electrons from the Lewis base to the Lewis acid?