Which of the following statements regarding the safe harbor rules for Section $401($k$)$ plans is$($are$)$ CORRECT?

The employer can avoid ACP and ADP testing if it matches $100\%$ up to $4\%$ of compensation for nonhighly compensated employees.

The employer can avoid ACP and ADP testing if it makes contributions of $3\%$ or more of compensation for all employees who are eligible to participate in the plan, whether or not the employee chooses to participate.

To meet the safe harbor requirements, the matching and nonelective contributions must be immediately $100\%$ vested.

The employer must provide notice to each eligible employee about rights and obligations under the plan.

$3$ and $4.$

$2$ and $3$

$4$ only.

$1,2,3,$ and $4.$