Help to reaolve this problem?

Answer:
B 0.2134*10^4
Step-by-step explanation:
Thumb rule to write any number in decimal form is that count the number digits after decimal and multiply the number with that number to the power of ten.
Here in this case In Option B 0.2134*10^4
there are 4 digits after decimal hence we multiply with 10 to the power 4 get the 21,340 which is the required result.