1. The roots are generally tap roots.
2. Roots in some genera have fungal association in the form of mycorrhiza
3. Some others small specialised roots called coralloid roots are associated with N2- fixing cyanobacteria.
( a ) 2 is incorrect; 1 and 3 are correct
( b ) 1 is incorrect; 2 and 3 are correct
( c ) 3 is incorrect; 1 and 2 are correct
( d ) All are correct