Correct Answer: (a) Karst Region
Solution:A steephead valley, or Blind valley is a deep, narrow, flat bottomed valley with an abrupt ending. Such valleys arise in limestone or Karst landscape. Blind valleys form in areas with soluble rocks like limestone, where underground water dissolves the rock, creating sinkholes and underground drainage systems. The valley abruptly ends, as the watercourse disappears underground. The valley floor is relatively flat. The sides of the valley are steep, forming a "steephead". Blind valleys are a common feature of karst topography, a landscape characterized by caves, sinkholes, and underground rivers.