Even though I'm not a designer (I'm on the board fab side of
          the fence), if I understand the statement correctly, the
          answer would be (C) .010" grid.  The fact that the lines are
          .008" wide would mean an encroachment of 1/2 that, or .004"
          on each side of the line center, thus leaving .006" of
          spacing to the nearest pad.  There would also be .012" of
          space left between the lines.
          Unfortunately, in the real world, we board fabricators would
          much rather see the spaces spread out evenly; i.e., if there
          is .040" of spacing between pads with (2) .008" lines, there
          would be .024" left (.040" - .008" -.008") for three spaces
          (pad-to-line, line-to-line, and line-to-pad), or .008"
          apiece.  On a .010" grid, the biggest gap would occur
          between the two lines (.012").  More spacing would be
          preferred from pad-to-line, especially for soldermask.
          Maybe the answer isn't (C)...hmmm.  Perhaps the IPC could
          come out with a new parlor board game: "Trivial Pursuit -
          pwb design edition".
          Regards (and happy holidays),
          Tom Coyle
          Field Services Engineer
          HADCO Corporation
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