Solution:(b) The municipal corporation has demarcated walking zones using paints and cones.(a) Walking zones are demarcating the municipal corporation using paints and cones. (Incorrect placement of Subject)
(b) The municipal corporation has demarcated walking zones using paints and cones. (Correct)
(c) The municipal corporation will demarcate walking zones using paints and cones. (Incorrect Tense)
(d) The municipal corporation is demarcating walking zones using paints and cones. (Incorrect Tense)