The circuit shown in the figure is a 4-bit DAC The input bits 0 and 1 are represented by 0 and 5 V, respectively. The OP AMP is ideal, but all the resistances and the 5 V inputs have a tolerance of ± 10%. The specification (rounded to the nearest multiple of 5%) for the tolerance of the DAC is
(a) ±35% (b) ±20%
(c) ±10% (d) ±5%