Which description matches the transformations y = cos x undergoes to
produce y = -3 cos(x) + 1 ?
A. Reflection across the y-axis, vertical shift up by 1 unit, horizontal
shift right by 3 units
B. Vertical stretch by factor 3, reflection across the x-axis, then a
vertical shift up 1 unit
C. Horizontal compression by factor 3, vertical shift by 1 unit up, then
a reflection across the x-axis
D. Horizontal shift left 3 units, then vertical shift up by 1 unit