-14/31 and -17/33
-17/33 - (-14/31) = (-17/33*31/31) - (-14/31*33/33) = -527/1023 + 462/1023
= (-527+462)/1023 = -65/1023
-65/1023 ÷ 2 = -65/1023 * 1/2 = -65/2046
-17/33 - (-65/2046) = (-17/33*62/62) - (-65/2046) = -1054/2046 + 65/2046
= -989/2046 Choice C.