What is the metric equivalent of a 1 by 4?

A 1 by 4 board in nominal measurements refers to a piece of lumber that is approximately 1 inch thick and 4 inches wide. When converting to metric measurements, the industry standard is that the actual dimensions of a 1 by 4 are typically around 19 mm thick by 89 mm wide, but it can also be commonly expressed as 19 mm by 76 mm for specific applications.

The correct answer accurately reflects the standard dimensions of a 1 by 4 board in the metric system. The dimensions listed as 19 mm by 76 mm show a close representation of the actual dimensions of lumber in other sizes, emphasizing the common practice of rounding to whole numbers for ease of reference.

Other options do not correspond to the common actual sizes of a 1 by 4. The measurements in those choices either exceed the standard length and width used for a 1 by 4 or do not match the typical proportions found in the lumber industry, making them less applicable in this context.