Question : Using $\tan (A-B)=\frac{\tan A-\tan B}{1+\tan A \tan B}$, find the value of $\tan 15°$.

Option 1: $\sqrt{3}+1$

Option 2: $\sqrt{3}-1$

Option 3: $2-\sqrt{3}$

Option 4: $2+\sqrt{3}$

Question : The value of $\left(2 \cos ^2 \theta-1\right)\left[\frac{1+\tan \theta}{1-\tan \theta}+\frac{1-\tan \theta}{1+\tan \theta}\right]$ is:

Option 1: $2$

Option 2: $0$

Option 3: $\frac{\sqrt{3}}{2}$

Option 4: $1$

Question : The value of $\tan 5^{\circ} \tan 25^{\circ} \tan 45^{\circ} \tan 65^{\circ} \tan 85^{\circ}$ is ______.

Option 1: 4

Option 2: 3

Option 3: 1

Option 4: 2