6. The prime numbers $p_{1}, p_{2}, p_{3}$ form an arithmetic sequence with a common difference of 80. The number of such sequences is $(\quad)$.
A. 1
B. 2
C. 3
D. infinitely many
6. A.

First, $p_{1} \geqslant 3, p_{2}=P_{1}+80=3 \times 26+(p_{1}+2), p_{3}=p_{1}+160=3 \times 53+(p_{1}+1)$.
Thus, $p_{1}$, $p_{2}$, $p_{3}$ must have one that is divisible by 3, so $p_{1}$ can only be 3, and $3$, $83$, $163$ are all prime numbers.