1.If z=a+ibz = a + ibz=a+ib satisfies arg(z−1)=arg(z+3i)\arg(z - 1) = \arg(z + 3i)arg(z−1)=arg(z+3i), then (a−1):b=(a - 1) : b =(a−1):b=a.2:12 : 12:1b.1:31 : 31:3c.−1:3-1 : 3−1:3d.None of theseLogin to continueOnly logged in users canattempt or see the solution.