The tangent at a point on $16 \mathrm{x}^{2}+25 \mathrm{y}^{2}=400$ meets the tangents at the ends of the major axis at $\mathrm{T}_{1}$ and $\mathrm{T}_{2} .$ Then the equation of the circle with on $\mathrm{T}_{1} \mathrm{~T}_{2}$ as diameter passes through the point
(a) $(1,0)$
(b) $(3,0)$
(c) $(0,3)$
(d) $(0,-3)$