The line $lx + my + n = 0$ will be a tangent to the circle ${x^2} + {y^2} = {a^2}$ if
The line $lx + my + n = 0$ will be a tangent to the circle ${x^2} + {y^2} = {a^2}$ if
- A
${n^2}({l^2} + {m^2}) = {a^2}$
- B
${a^2}({l^2} + {m^2}) = {n^2}$
- C
$n(l + m)a$
- D
$a(l + m) = n$
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