If $3 \sin \theta+4 \cos \theta=3$ and $\theta \neq(2 n+1) \frac{\pi}{2}$ then $\sin 2 \theta=$

• A

  $\frac{336}{625}$
• B

  $-\frac{7}{25}$
• C

  $\frac{24}{25}$
• Correct answer
  D

  $-\frac{336}{625}$

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