What does it mean when a function is one-to-one?

Let a function be defined from A to B then f is said to be one to one function if every element of domain has its unique image in co- domain . In other words, if each separate elements of set A are mapped with separate of set B then such function is known as one to one function.

answer: i believe c. is the answer sorry if i am wrong

step-by-step explanation:

for ex: the reciprocal of 3/4 is 4/3. it is the opposite.

reciprocal definition:

a mathematical expression or function so related to another that their product is one; the quantity obtained by dividing the number one by a given quantity.