what is the geometric description of the function represented by a matrix (0 1, -1 0) in R2 .. i need the correct option ?

Consider te matrix acting on a vector [x , y]:

[0  1] [ x]      [ y]

[-1 0] [ y ]  = [-x] 

If you define a new coordinate system in R2 such that

x' = x*cos(q) + y*sin(q)     y' = -x*sin(q) + y*cos(q)   where q is a rotation of the x-y axis  then

x' = y = x*cos(q) + y*sin(q)   y' = -x = -x*sin(q) + y*cos(q)  and setting q = pi/2 givens

x' = y  y' = -x 

so this matrix is a rotation of the x-y coordinate axis by pi/2