3. In space, there are four different planes. The set of possible numbers of intersection lines formed by these four planes is ( ).
(A) $\{1,2,3,4,5,6\}$
(B) $\{0,1,2,3,4,5,6\}$
(C) $\{0,1,3,4,5,6\}$
(D) $\{0,1,2,3,5,6\}$
3. (C).

If four planes are parallel to each other, the number of intersection lines is 0;
If these four planes are like an open book with only four pages, the number of intersection lines is 1;

If three planes are parallel to each other, and the fourth plane intersects with them, the number of intersection lines is 3;

If the four planes are exactly the four side planes of a cube, the number of intersection lines is 4;

If two planes are parallel, and the other two planes are not parallel and intersect with the first two planes, it can form 5 intersection lines;

If four planes intersect to form a tetrahedron, there are 6 intersection lines, and the situation where four planes have exactly two intersection lines does not exist. Therefore, the set that satisfies the conditions of the problem is $\{0,1,3,4,5,6\}$.