Number of letters skipped in between adjacent letters in the series are multiples of 3.
Which of the following series observes this rule ?

A. AELPZ

Number of letters skipped in between adjacent letters in the series decrease by two.
Which of the following series observes this rule ?

B. GPWBE

Number of letters skipped in between adjacent letters in the series decrease by one.
Which of the following series observes this rule ?

D. DBYUP

In which of the following letter sequences, there is a letter leaving two letters of the alphabet in order, after the letters placed at odd-numbered positions and leaving one letter of the alphabet in order at even-numbered positions ?

A. ADFIKN

Number of lettters skipped in between adjacent letters in the series increases by one.
Which of the following series observes this rule ?

D. IKNRW