Study the following information carefully and answer the questions given below:

Six persons are arranged in descending order according to their weight from left to right. Only T is lighter than Q whose weight is 17kg. S is twice heavier than Q and 14 kg lighter than N. Two persons between M and S. R is not the second heaviest among all.

Who is the heaviest among all?

The correct answer is M.

Let us determine the descending order of the six persons from left to right (from heaviest to lightest) step-by-step based on the given information:
Let the positions from left to right be represented as:
1 > 2 > 3 > 4 > 5 > 6 (where 1 is the heaviest and 6 is the lightest).

Step 1: Position of Q and T
We are given that "Only T is lighter than Q". This means Q is in the 5th position and T is in the 6th (lightest) position.
So, the arrangement is:
_ > _ > _ > _ > Q > T
The weight of Q is given as 17 kg.

Step 2: Calculate weights of S and N
S is twice heavier than Q:
$\text{Weight of S}=\; 2\; \times \; 17\; =\; 34\text{kg}$
S is 14 kg lighter than N, which means N is 14 kg heavier than S:
$\text{Weight of N}=\; 34\; +\; 14\; =\; 48\text{kg}$

Step 3: Positions of M and S
We are given that there are "Two persons between M and S". The remaining positions for M and S are 1, 2, 3, and 4. The only way to have exactly two persons between them is if they occupy positions 1 and 4.
Since N is heavier than S ($48\text{kg}>34\text{kg}$), S cannot be at position 1 (the heaviest position). Therefore, S must be at position 4, and M must be at position 1.
The arrangement now is:
M > _ > _ > S > Q > T

Step 4: Positions of N and R
The remaining two positions are 2 and 3, which must be occupied by N and R. We are given that "R is not the second heaviest among all" (position 2 is the second heaviest position). Thus, R cannot be at position 2. This leaves position 3 for R and position 2 for N.
The final descending order of weights is:
M (Heaviest) > N (48 kg) > R > S (34 kg) > Q (17 kg) > T (Lightest)

Comparing all positions, we find that M is the heaviest among all.