Scalar or Matrix?

For column vectors x,y∈Rnx, y \in \mathbb{R}^n, what are x⊤yx^\top y and xy⊤xy^\top respectively?

A

Both x⊤yx^\top y and xy⊤xy^\top are n×nn \times n matrices

B

x⊤yx^\top y is a scalar; xy⊤xy^\top is an n×nn \times n matrix (the outer product)

C

x⊤yx^\top y is an n×nn \times n matrix; xy⊤xy^\top is a scalar

D

Both x⊤yx^\top y and xy⊤xy^\top are scalars