4. The distance between any two neighboring marks on the real number line shown below in one centimeter. The total distance between the -10 mark and the 10 mark is A. $0 \mathrm{~cm}$ B. $100 \mathrm{~cm}$ C. $20 \mathrm{~cm}$ D. Cannot be determined accurately.

Step 1 ：The distance between any two neighboring marks is 1 cm. The marks are integers from -10 to 10. So, we need to calculate the total number of marks between -10 and 10, and then multiply it by 1 cm to get the total distance.

Step 2 ：total_marks = 21

Step 3 ：total_distance = total_marks * 1 cm

Step 4 ：Final Answer: The total distance between the -10 mark and the 10 mark is \(\boxed{21 \mathrm{~cm}}\)