question_answer

For which condition does the equation \[px+qy+r=0\] represent a linear equation in two variables?

A) \[p\ne 0,\,\,q=0\]                       

B) \[q\ne 0,\,\,q=0\]

C) \[p=0,\,\,q=0\]  

D)        \[p\ne 0,\,\,q\ne 0\]