The small divisions are quarters.
Remember we have to count to the left of zero for A and B and to the right of zero for C and D.
Start at A to the left of zero, so A is negative: it is 2 quarters to the left of -1 so 2/4=1/2 and A must be -1 1/2.
B is between 0 and -1 and is 3/4 to the left of zero at -3/4.
C is between 0 and 1 at 3/4. C is the opposite of B.
D is between 1 and 2 at 1 3/4.