Choose or find odd letter group - RTW , QOM , IKG , IKM , BDF

A. RTW

A blacksmith has five iron articles A, B, C, D and E, each having a different weight.
(i)  A weights twice as much as B.
(ii)  B weights four and a half times as much as C.
(iii)  C weights half as much as D.
(iv)  D weights half as much as E.
(v)  E weights less than A but more than C. Which of the following articles is the heaviest in weight ?

A. A

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

In the following question, a matrix of certain characters is given. These characters follow a certain trend, row-wise or column-wise. Find out this trend and choose the missing character accordingly.
Z4 X3 V9
A6 C2 ?
T5 R4 P15

B. E12

Choose or find odd letter group - PENAL , IDHNI , RUUD , KRTSINSA

A. PENAL