View factor of a large cylinder of 10cm in radius and 60cm in length from a co-axial smaller cylinder of 5cm radius and the same length is 0.34. View factor of the large cylinder of itself (concave inner surface) is 0.25. The view factor of the larger cylinder with respect to either annular end is (a) 0.17 (b) 0.29 (c) 0.58 (d) 0.41