What is the electron configuration for rubidium?

A. 1s²2s²2p 3s²3p63d¹04s²4p65s¹
B. 1s²2s²2p 3s²3p63d¹04s²4p65s¹
C. 1s²2s²2p 3s²3p64s²3d¹04p65s¹
D. 2016135²31