Let \( A=\{x\in \mathbb{R}:[x+3]+[x+4]\le 3\} \), \( B=\left\{x\in \mathbb{R}:3^{x}\left(\displaystyle\sum_{r=1}^{\infty}\dfrac{3}{10^{r}}\right)^{x-3}<3^{-3x}\right\} \), where \([t]\) denotes greatest integer function. Then:
\( A\cap B=\phi \)
\( A=B \)
\( B\subset C,\; A\ne B \)
\( A\subset B,\; A\ne B \)