Answer:

Explanation:
The starting value is

Now, the whole part of a scientific must between 0 and 9, and we will preserve the same number of significant digits, that is, the same digits will remains.
Also, observe that the decimal point is between 5 and 6. We need to move the decimal point between 1 and 6, as follows

Then, count the number of spots we moved the decimal point. We moved 3 spots, that meanst the exponent of the scientific notation is 3. Applying all these things, we have

Therefore, the right answer is the last choice.