The following is A. 1:2

B. 2:1

C. 2:3

D. 3:2

From the map, we can count the number of general stores is 6 and the number of the ground is 4.

∴

⇒

⇒

Option (a) is not match to our solution. so it is not a correct answer.

(b) is not match to our solution. so it is not a correct answer.

(c) is not match to our solution. so it is not a correct answer.

(d) is the correct answer and matches our solution.