Mathematics

Problem

Which of the following best characterises a surjective (onto) function

f\!:\!A\to B

? a) Every element of

A

is mapped to a distinct element of

B

. b) Every element of

B

is the image of exactly one element of

A

. c) Every element of

B

is the image of at least one element of

A

. d)

f

has an inverse defined on all of

B