Final answer:
The number 2,156 is expressed in scientific notation as 2.156 × 10³, which is option B from the provided choices.
Step-by-step explanation:
To express the number 2,156 in scientific notation, we must first move the decimal point so that there is only one non-zero digit to the left of the decimal.
For the number 2,156, we move the decimal point three places to the left to get 2.156. Since we moved the decimal point three places, we must multiply by 10 raised to the power of 3.
Therefore, the number 2,156 expressed in scientific notation is 2.156 × 10³.
The correct answer from the options provided is B. 2.156 × 10³.