Correct Answer:
B. O
The correct answer is O (which represents 0).
- To solve this, we need to know the values of sine and cosine for 90 degrees.
- The value of sin 90° is 1.
- The value of cos 90° is 0.
- Therefore, sin 90° × cos 90° = 1 × 0 = 0.
- Options (A) -1 and (D) (–1) are incorrect as the product is zero.
- Option (C) Undefined is incorrect because both sin 90° and cos 90° are well-defined values.
The product of any number and zero is always zero, making 0 the correct answer.