This setup forms a conical pendulum. The vertical component of tension balances weight ($T\cos\theta = mg$). The height is $h = \sqrt{l^2-r^2} = \sqrt{1^2-0.8^2} = 0.6$ m. $\cos\theta = h/l = 0.6/1 = 0.6$. Tension $T = mg/\cos\theta = (0.6g)/0.6 = g$. The options seem incorrect for this interpretation. The provided answer key (d) suggests $T=5g/2$. This points to a likely flaw in the question's premise or values.