An insect differs from a spider in having

• A
  $3$ pairs of legs and $2$ pairs of wings instead of $4$ pairs of legs and no wings
• B
  $3$ pairs of legs and $2$ pairs of wings instead of $3$ pairs of legs and no wings
• C
  $3$ pairs of legs and no wings instead of $5$ pairs of legs and generally one pair of wings
• D
  $6$ pairs of legs and one pair of wings instead of $4$ pairs of legs and no wings