Let K be a real number such that the system
∣10+12i−z∣=4 and ∣z−6−K∣=∣z−2i−K∣ has exactly one complex solution z. The sum of all possible values of K, can be written as nm, where m and n are relatively prime integers then m+n equals :
(A) 20
(B) 21
(C) 22
(D) 23