The first letters of the 1st, 2nd, 3rd, 4th and 5th terms are moved three, four, five, six and seven steps ahead respectively to obtain the first letter of the successive terms. The second lettrs of the 1st, 2nd, 3rd, 4th and 5th are moved five, six, seven, eight and nine steps forward respectively to obtain the second letter of the successive terms. Similarly, the third letters of the 1st, 2nd, 3rd, 4th, and 5th terms are moved seven, eight, nine, ten and eleven steps forward respectively to obtin the third letter of the successive terms. Hence, option (C) is the correct answer. Hence, option (C) is the correct answer.

The 1st letter of each term is moving one step forward and the 2nd letter is moving one step backward to obtain the corresponding letters of the next term. Hence, option (A) is the correct answer.

The 1st letter of each term is moving one step forward, the 2nd letter is moving four steps backwards and the 3rd letter is moving four steps forward to get the corresponding letters of the next term. Hence, option (D) is the correct answer.

The 1st letters of the first, second, third and fourth terms re moving one, two, three, and four steps forward respectively to get the first letter of the succesive terms. The 2nd letters of the first, second, third and fourth terms are moving three, four, five and six steps backward respectively to obtain the second letters of the successive terms. The last letters of the terms are alternate. Hence, option (C) is the correct answer.

The 1st, 4th, 7th and 9th letters of the series are in alphabetical order. So, the 10th letter would be the letter after "D" is "E". Further, the 2nd and 3rd letter are alternate and in reverse order and so are the 9th and 10th letters and the 11th and 12th. Hence, option (A) is the correct answer.

The term has two series - 1st one: Z, X, V, T, ? and the 2nd one is: L, J, J, F, ? both series are consist of alternate letters in reverse order.

The letters are alternately moved one and two steps backward to get the successive terms. Hence, option (D) is the correct answer.

The 1st letter of each term is moving three steps forward and the last letter is moviing two steps backward to obtain the corresponding letters of the next term. The number follow the sequence
x 2 + 1, x 2 + 2, x 2 + 3, x 2 + 4. So, the wrong number is 10 and it should be replaced by
(4 x 2 + 1) i.e 9. Hence, option (B) is the correct answer.

The 1st letter of each term is moving three steps forward and the last letter is moving three steps backward to get the corresponding letters of the next term. The number form the
sequence 2², 2², 3², 4², 5². Hence, option (A) is the correct answer.

All letters of each term are moving 9 steps forward to get the corresponding letters of the next term. Hence, option (C) is the correct answer.