7. Classify each of the following functions as: injection, surjection, bijection, or none. Give the most specific answer. a) f-(a,1), (b, 2), (c, 2), (d, 3)) for domain space (a, b, c, d) and range space (1, 2, 3, 4) b)f-((a, 1), (b, 2), (d, 3), (c, 5)) for domain space (a, b, c, d) and range space 1, 2, 3, 4, 5) c) f-((a, 1), (b, 2), (c, 4), (d, 3)) for domain space (a, b, c, d) and range space (1, 2, 3, 4) d) f-(a, 1), (b, 2), (c, 4), (d, 3), (e,1)) for domain space (a, b, c, d, e and range space e) f(x) cos(x) when both domain and range space are R. f f(x) 3x+2 when both domain and range space are R. g) f(x)x+1 when both domain and range space are positive R