; and (B) with respect to an employee whose annual rate of basic pay is not less than $200,000, not more than $5,000 reduced by employer payroll taxes (as so defined) with respect to such premium pay. (b) Pay (1) In general With respect to the covered period, an employee is entitled to be paid the applicable differential established under subsection (a) for any period, including any period during the covered period that precedes the date of enactment of this Act, in which the employee is carrying out covered duty, subject to the applicable limitations under that subsection. (2) Retroactive payment With respect to a payment earned by an employee under this section for a period during the covered period that precedes the date of enactment of this Act, the employee shall be paid that payment in a lump sum payment as soon as is practicable after that date of enactment. (3) Limitation on entitlement An employee shall be entitled to be paid the applicable differential established under subsection (a) only to the extent that amounts provided in this title will be made available to such employee’s agency pursuant to section 170204(c)(1) in an amount sufficient to provide such applicable differential to all such eligible employees. (c) Guidance and regulations (1) Executive branch (A) In general The Office of Personnel Management shall develop criteria for agencies in the executive branch of the Federal Government regarding the means by which to determine the eligibility of an employee in such an agency for the pay differential established under this section, which shall— (i) be based on— (I) the duties performed by the employee; (II) the setting in which the employee performs the duties described in subclause (I); and (III) the interactions with the public required in order for the employee to perform the duties described in subclause (I)