In a box containing 100 bulbs, 10 are defective. The probability that out of a sample of 5 bulbs, none is defective is

$(\frac{9}{10})^5$

The correct answer is Option (2) → $(\frac{9}{10})^5$

Total bulbs $=100$

Defective bulbs $=10$

Good bulbs $=90$

Probability that one bulb is good

$=\frac{90}{100}=\frac{9}{10}$

Probability that all $5$ bulbs are good

$=\left(\frac{9}{10}\right)^5$

The required probability is $\left(\frac{9}{10}\right)^5$.