A sample originally contained $10^{20}$ radioactive atoms, which emit $\alpha$-particles. The ratio of $\alpha$ particles emitted in the third year to that emitted during the second year is $0.3$. How many $\alpha$ particles were emitted in the first year?

• A

  $3 \times 10^{18}$
• Correct answer
  B

  $3 \times 10^{19}$
• C

  $5 \times 10^{18}$
• D

  $7 \times 10^{19}$

Hence, the correct answer is option: 'B'.