Which of the following series observes the rule, "Skip in between adjacent letters, increasing one letter more each time to build a set of letters" ?

Answer: B. BDGKPV
B C D E  F G H  I  J K L  M  N  O P Q  R  S  T  U V
  1   2   3   4   5  
    +1   +1   +1   +1