The vector from \( B(3, -4, 7) \) to \( A(2, -3, 5) \) is given by: \[ \overrightarrow{BA} = (x_2 - x_1)\hat{i} + (y_2 - y_1)\hat{j} + (z_2 - z_1)\hat{k}, \] where \( (x_1, y_1, z_1) \) are the coordinates of point \( B \), and \( (x_2, y_2, z_2) \) are the coordinates of point \( A \).
Substituting the given coordinates: \[ \overrightarrow{BA} = (2 - 3)\hat{i} + (-3 - (-4))\hat{j} + (5 - 7)\hat{k}. \]
Simplify each term: \[ \overrightarrow{BA} = (-1)\hat{i} + (1)\hat{j} + (-2)\hat{k}. \]
Thus: \[ \overrightarrow{BA} = -\hat{i} + \hat{j} - 2\hat{k}. \]
Hence, the vector is \(-\hat{i} + \hat{j} - 2\hat{k}\), and the correct answer is (D).

A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:
(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?