As the state of strain of an element of dense sand changes from plain strain to trivial condition, the effective angle of internal friction :

ANS:B - decreases

IF Dense sand is Sheared initially it will undergo compression & later interlocking b/w particles breaks and soil start to behave like loose sand; DILATION Occurs.

Loose sand: "coefficient of the angle of friction is less" (therefore "Less Strength ").
Dense sand: "coefficient of the angle of friction is More" (therefore "More Strength").