What should be the size of an external door of a residential building?

• A. (1.0 m x 3 m) to (2.1 m x 3 m)
• B. (1.0 m x 2 m) to (1.1 m x 2 m)
• C. (2.0 m x 2.1 m) to (2.1 m x 3 m)
• D. (1.0 m x 2.9 m) to (2.1 m x 3 m)