`PQR` is a triangular park with `PQ=PR=200m`. A.T.V. tower stands at the mid-point of `QR`. If the angles of elevation of the top of the tower at `P`, `Q` and `R` are respectively `45^(ulo)`, `30^(ulo)` and `30^(ulo)` then the height of the tower (in m ) is
A. `100sqrt(3)`
B. `50sqrt(2)`
C. `100`
D. `50`
