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The multiplicity of a zero represents the number of times a factor is repeated in the factorization of the polynomial. If a graph crosses the x-axis at a certain zero, it means that the factor corresponding to that zero changes sign as it crosses the x-axis. In other words, the multiplicity must be an odd number.
Therefore, the multiplicity of a zero whose graph crosses the x-axis cannot be 2 (Option #1) or 4 (Option #3), since both of these are even numbers.
The only valid option is therefore Option #2: 3.