The value of the expression $$\left[ \cosec(75^\circ + A) - \sec(15^\circ - A) - \tan(55^\circ + A) + \cot(35^\circ - A) \right]$$​ is:

Given expression:
​$$\cosec(75^\circ + A) - \sec(15^\circ - A) - \tan(55^\circ + A) + \cot(35^\circ - A)$$​​
Use trigonometric identities:
​$$\csc(90^\circ - x) = \sec(x) \\\tan(90^\circ - x) = \cot(x)$$​​
Now observe:
​$$\cosec(75^\circ + A) = \csc[90^\circ - (15^\circ - A)] = \sec(15^\circ - A) \\\tan(55^\circ + A) = \tan[90^\circ - (35^\circ - A)] = \cot(35^\circ - A)$$​​
So the expression becomes:
​$$\sec(15^\circ - A) - \sec(15^\circ - A) - \cot(35^\circ - A) + \cot(35^\circ - A)$$​​
Which simplifies to:
0
Correct answer is (b)