For a vector $E$, which one of the following statements is $\text{NOT TRUE}$?
- If $\Delta.E=0,\;E$ is called solenoidal
- If $\Delta \times E=0,\;E$ is called conservative
- If $\Delta\times E=0,\;E$ is called irrotational
- If $\Delta.E=0,\;E$ is called irrotational