Final answer:
Graph (d) is the correct graph representation of the 6th-degree polynomial function with the given characteristics.
Step-by-step explanation:
The graph that could represent a 6th-degree polynomial function with 3 distinct zeros, 1 zero with a multiplicity of 3, and a negative leading coefficient is graph (d).
Graph (d) begins with a nonzero y-intercept with an upward slope that levels off at zero (Part A). It then starts at zero with a downward slope that decreases in magnitude until the curve levels off (Part B). Finally, it begins at zero with an upward slope that increases in magnitude until it becomes a positive constant (Part C).