Which of the following represents the electronic configuration of a transition element?

• A
  $1s^2, 2s^2 2p^6 \dots ns^2 np^3$
• B
  $1s^2, 2s^2 2p^6 \dots (n-1)d^{1-10} ns^{1-2}$
• C
  $1s^2, 2s^2 2p^6 \dots ns^2 np^6 d^{10}, (n+1)s^2 p^1$
• D
  $1s^2, 2s^2 2p^6 \dots ns^2 np^6$