1. Human red blood cells are about 11.0 μm in diameter. 2. Nerve cells are some of the largest cells. 3. Cells also vary greatly in their shape; they may be disc-like, polygonal, columnar, cuboid, thread like, or even irregular. Regarding 1,2 and 3:

Question

( a ) 3 is incorrect; 1 and 2 are correct
( b ) 3 is correct but 1 and 2 are incorrect
( c ) 1 is incorrect but 2 and 3 are correct
( d ) 2 is incorrect but 1 and 3 are correct