Correct Option: C. 12 kilometre Explanation of the Correct Answer To determine the length of the main road to the nearest kilometre, we need to understand what "to the nearest kilometre" means. This phrase indicates that we should round the length of the road to the closest whole number of kilometres.

1. Understanding Rounding:
2. When rounding to the nearest whole number, if the decimal part is 0.5 or higher, we round up. If it is less than 0.5, we round down.
3. For example, if the length of the road were 11.4 km, we would round it down to 11 km. If it were 11.5 km, we would round it up to 12 km.
4. Evaluating the Options:
5. The options provided are 7 km, 10 km, 12 km, and 14 km.
6. To determine which option is correct, we need to consider the context or any additional information that might suggest the actual length of the road. However, since we are given that the correct answer is 12 km, we can infer that the actual length of the road, when rounded, is closest to 12 km.
7. Why 12 km is Correct:
8. If the actual length of the road were, for example, 11.5 km, it would round to 12 km.
9. If it were 12.4 km, it would still round to 12 km.
10. Therefore, the length of the road must be in a range that rounds to 12 km, which is between 11.5 km and 12.4 km.

Explanation of Why Other Options are Incorrect

• Option A: 7 km:
• This option is too far from the length of 12 km. If the actual length were around 7 km, it would not round to 12 km. It would round to 7 km if it were between 6.5 km and 7.4 km.
• Option B: 10 km:
• Similar to option A, 10 km is also too far from 12 km. The only way 10 km could be correct is if the actual length were between 9.5 km and 10.4 km, which does not support the given correct answer of 12 km.
• Option D: 14 km:
• This option is also incorrect as it is too high. If the actual length were around 14 km, it would round to 14 km if it were between 13.5 km and 14.4 km, which again does not support the correct answer of 12 km.

Summary of Key Points

• Rounding to the nearest kilometre means adjusting the number based on the decimal part.
• The correct answer, 12 km, suggests that the actual length of the road is closest to this value when rounded.
• Other options (7 km, 10 km, and 14 km) are incorrect as they do not align with the rounding rules that would lead to 12 km.
• Understanding rounding is crucial for accurately interpreting measurements in geography and other fields.

This thorough understanding of rounding and the evaluation of options will help you in similar questions in your geography exam.