3. Given that $\left\{ a _ { n } \right\}$ is an arithmetic sequence with non-zero common difference $d$, and the sum of the first $n$ terms is $S _ { n }$. If $a _ { 3 } , a _ { 4 } , a _ { 8 }$ form a geometric sequence, then A. $a _ { 1 } d > 0 , d S _ { n } > 0$ B. $a _ { 1 } d < 0 , d S _ { n } < 0$ C. $a _ { 1 } d > 0 , d S _ { n } < 0$ D. $a _ { 1 } d < 0 , d S _ { n } > 0$ [Figure]
3. Given that $\left\{ a _ { n } \right\}$ is an arithmetic sequence with non-zero common difference $d$, and the sum of the first $n$ terms is $S _ { n }$. If $a _ { 3 } , a _ { 4 } , a _ { 8 }$ form a geometric sequence, then\\
A. $a _ { 1 } d > 0 , d S _ { n } > 0$\\
B. $a _ { 1 } d < 0 , d S _ { n } < 0$\\
C. $a _ { 1 } d > 0 , d S _ { n } < 0$\\
D. $a _ { 1 } d < 0 , d S _ { n } > 0$\\
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