a) 10 m
b) 2 m
c) 1.50 m
d) 15 m

Answer: c
Explanation: Test Pit is excavated up to a depth about 1.50 m at which sufficiently hard soil is available. The various data of soil can be inspected, studied and classified accordingly. This method is useful when hard soil is available within a maximum depth of 1.50 m.