Delete rows from matrix

Let's say we have matrix A=[1 2 3; 4 5 6; 7 8 9; 10 11 12], and b a number the user is inserting.

I want to delete 1st row if b=1, or delete the 2nd row if b=2 etc. Is this possible?

Answer 1

[madhan ravi]

A=[ 1  2  3;...
    4  5  6;...
    7  8  9;...
    10 11 12]
b=2;
A(b,:)=[]

Answer 2

[KSSV]

b = 1 ; 
A(b,:) = [] ;