In the tangential method of techeormetry, the following notations have been used:

α₁ = angle of elevation corresponding to the upper vane

α₂ = angle of elevation corresponding to the lower vane

S = distance between the vanes - staff intercept

D = horizontal distance

V = vertical distance

In this context, match list I (Quantity to be computed under the given conditions) with List II (Equation to be used) and select the correct answer using the codes given below the lists :

List I List II

A. 'D' when both the angles are angles of elevation 1. \(\frac{{S\tan {\alpha _2}}}{{\tan {\alpha _2} - \tan {\alpha _1}}}\)

B. 'V' when both the angles are angles of elevation 2. \(\frac{S}{{\tan {\alpha _2} - \tan {\alpha _1}}}\)

C. 'D' when one angle is the angle of elevation and the other that of depression 3. \(\frac{{S\tan {\alpha _2}}}{{\tan {\alpha _1} - \tan {\alpha _2}}}\)

D. 'V' when both angles are angles of depression 4. \(\frac{S}{{\tan {\alpha _1} - \tan {\alpha _2}}}\)

Question

	List I		List II
A.	'D' when both the angles are angles of elevation	1.	\(\frac{{S\tan {\alpha _2}}}{{\tan {\alpha _2} - \tan {\alpha _1}}}\)
B.	'V' when both the angles are angles of elevation	2.	\(\frac{S}{{\tan {\alpha _2} - \tan {\alpha _1}}}\)
C.	'D' when one angle is the angle of elevation and the other that of depression	3.	\(\frac{{S\tan {\alpha _2}}}{{\tan {\alpha _1} - \tan {\alpha _2}}}\)
D.	'V' when both angles are angles of depression	4.	\(\frac{S}{{\tan {\alpha _1} - \tan {\alpha _2}}}\)