A rectangular carpet is $4 \mathrm{~m}$ long and $6 \mathrm{~m}$ wide. Choose the option on the centimetre square grid below which shows a scale diagram of the carpet using the scale $1 \mathrm{~cm}$ represents $2 \mathrm{~m}$.

Step 1 ：Given a rectangular carpet with length \(4 \mathrm{~m}\) and width \(6 \mathrm{~m}\), and a scale of \(1 \mathrm{~cm}\) represents \(2 \mathrm{~m}\)

Step 2 ：Calculate the dimensions of the carpet in centimeters using the given scale: \(length_{cm} = length_{m} \times scale\) and \(width_{cm} = width_{m} \times scale\)

Step 3 ：\(length_{cm} = 4 \mathrm{~m} \times 0.5 = 8.0 \mathrm{~cm}\) and \(width_{cm} = 6 \mathrm{~m} \times 0.5 = 12.0 \mathrm{~cm}\)

Step 4 ：\(\boxed{\text{The scale diagram of the carpet should be 8 cm long and 12 cm wide}}\)