Answer:
Option B and Option D.
Explanation:
Among the options, only B and D represent identities, they are known has pythagorean identities because they are obtained form a right triangle and its trigonometry.
All pythagorean identities are
![sin^(2)\alpha+cos^(2) \alpha =1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/naasuwc32bl3ic5nslhx3xuwlvnp3eugj0.png)
![tan^(2)\alpha +1=sec^(2)\alpha](https://img.qammunity.org/2020/formulas/mathematics/middle-school/r2n6eyyci6hjrkht4u26r7s8lfvr49w7l9.png)
![cot^(2) \alpha +1=csc^(2) \alpha](https://img.qammunity.org/2020/formulas/mathematics/middle-school/u32szse9oftyqf2935dggtn3ivxrggcdpj.png)
If you compare only B and D represent two of these identities.
Option A and C don't represent identities because they are written wrong, if you compare with all three identities above, you will realize this.
Therefore, the right options are B and D.