The correct answer is: C. The outline of the base of the foundation of the dam.
Bligh’s creep theory states that percolating water flows along the outline of the base of the foundation of the dam. This is because the water is attracted to the foundation by capillary action. Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.
The other options are incorrect because they do not accurately reflect Bligh’s creep theory. Option A states that percolating water flows along a straight path under the foundation of the dam. However, this is not the case. The water actually flows along the outline of the base of the foundation, which is a curved path. Option B states that percolating water flows along a circular path under the foundation of the dam. This is also incorrect. The water does not flow in a circular path, but rather in a curved path that follows the outline of the base of the foundation. Option D states that percolating water does not flow along any particular path under the foundation of the dam. This is also incorrect. The water does flow along a particular path, which is the outline of the base of the foundation.