Dutch bond is a modification of English bond. In English bond, every other course is made up of headers, with stretchers in between. In Dutch bond, every other course is made up of headers and stretchers, with the headers alternating between being centered and offset. This creates a more visually appealing pattern than English bond.
Stretcher bond is a type of brickwork in which all of the bricks are laid as stretchers, with no headers. This type of bond is not very strong, and is not often used in structural applications.
Header bond is a type of brickwork in which all of the bricks are laid as headers, with no stretchers. This type of bond is very strong, and is often used in structural applications.
Single Flemish bond is a type of brickwork in which every other course is made up of headers and stretchers, with the headers alternating between being centered and offset. This type of bond is stronger than English bond, but not as strong as Dutch bond.
In conclusion, the correct answer to the question “Dutch bond is a modification of” is “English bond.”