Number of vertical joints in a stretcher course is x times the number of joints in the header course, where x is equal to A. $$\frac{1}{2}$$ B. 1 C. 2 D. $$\frac{1}{4}$$

The correct answer is $\boxed{\text{B}}$.

A stretcher course is a course of masonry laid with the bricks laid lengthwise, parallel to the face of the wall. A header course is a course of masonry laid with the bricks laid across the face of the wall.

In a stretcher course, there is one vertical joint for each brick. In a header course, there are two vertical joints for each brick. Therefore, the number of vertical joints in a stretcher course is twice the number of joints in the header course.