(a) Before entering upon their duties, all teachers shall execute a contract with their county boards, which shall state the salary to be paid and shall be in the form prescribed by the state superintendent. Each contract shall be signed by the teacher and by the president and secretary of the county board and shall be filed, together with the certificate of the teacher, by the secretary of the office of the county board. When necessary to facilitate the employment of employable professional personnel and prospective and recent graduates of teacher education programs who have not yet attained certification, the contract may be signed upon the condition that the certificate is issued to the employee prior to the beginning of the employment term in which the employee enters upon his or her duties.
(b) Each teacher's contract, under this section, shall be designated as a probationary or continuing contract. A probationary teachers contract shall be for a term of not less than one nor more than three years, one of which shall be for completion of a beginning teacher internship pursuant to the provisions of section two-b, article three of this chapter, if applicable. If, after three years of such employment, the teacher who holds a professional certificate, based on at least a bachelor's degree, has met the qualifications for a bachelors degree and the county board enter into a new contract of employment, it shall be a continuing contract, subject to the following:
(1) Any teacher with less than a bachelor's degree who holds a valid certificate and is employed in a county beyond the three-year probationary period shall be granted continuing contract status upon qualifying for the professional certificate based upon a bachelor's degree, if the teacher becomes reemployed; and