Final answer:
Option 'd', which is a set of ordered pairs (6,3), (9,3), (-14,3), clearly defines a function since each input has one unique output. Without visual representations of the other options, we cannot definitively say they are functions, although lines parallel to the x-axis typically are.
Step-by-step explanation:
The question provided involves determining which options represent a function. A function in mathematics is a relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output. An equivalent definition of a function is a relation such that no two different ordered pairs have the same first element.
Option 'd' lists a set of ordered pairs: (6,3), (9,3), (-14,3). All these pairs have different first elements (6, 9, and -14) and the same second element (3). Since there are no repeating first elements (which represent the inputs in a function), this set of ordered pairs satisfies the definition of a function.
Without the visual representation of pictures 1 and 2, we cannot ascertain whether they represent functions. However, description a indicates that all three pictures represent lines parallel to the x-axis. If indeed they are lines, each would be a function, as a line parallel to the x-axis would mean for each x-value, there is one unique y-value. Description b indicating that the lines in the pictures are mutually perpendicular does not provide enough information to determine if any are functions. We need to see if each line passes the Vertical Line Test (a tool to determine if a curve is a graph of a function or not).