Which of the following BEST explains the term 600 x 300 dpi?

Which of the following BEST explains the term 600 x 300 dpi?

A.
The resolution is 600 horizontal dots by 300 vertical dots per inch.

B.
The resolution is 600 lines per inch by 300 horizontal dots per inch.

C.
The saturation is 600 horizontal dots by 300 vertical dots per inch.

D.
The color depth is 600 vertical dots by 300 horizontal dots per inch.