1. In the Cartesian coordinate system, a point whose both coordinates are integers is called a "lattice point". On the triangle formed by the line $7 x+11 y=77$ and the coordinate axes, including the interior and the boundary, there are ( ) lattice points.
(A) 29
(B) 49
(C) 31
(D) 32
一, 1. B.
From the problem, we know that the number of interior lattice points of the triangle is $\frac{(7-1)(11-1)}{2}=30$, and there are a total of 19 lattice points on the boundary.