Q. In a triangle ABC with fixed base BC, the vertex A moves such that cosB cosC = 4sin2 A2. If a, b and c denote the lengths of the sides of the triangle opposite to the angles A, B and C, respectively, then

1. b + c = 4a
2. b + c = 2a
3. locus of point A is an ellipse
4. locus of point A is a pair of straight