PQR is a triangular park with PQ=PR=200 m. A TV tower stands at the mid-point of QR. If the angles of elevation of the top of the tower at P,Q and E are respectively 45o, 30o and 30o, then the height of the tower (in m) is
(a) 100
(b) 50
(c) 100 √3
(d) 50 √2