(a) Any board of education receiving notification of the existence of racial imbalance as specified in § 10-226b shall forthwith prepare a plan to correct such imbalance and file a copy of said plan with the State Board of Education. Said plan may be limited to addressing the imbalance existing at any school and need not result in a district-wide plan or district-wide pupil reassignment. A school district may request an extension of time in cases in which the number of students causing said imbalance is fewer than five students at a school.

(b) Any plan submitted by the board of education of any town under sections 10-226a to 10-226e, inclusive, shall include any proposed changes in existing school attendance districts, the location of proposed school building sites as related to the problem, any proposed additions to existing school buildings and all other means proposed for the correction of said racial imbalance. The plan shall include projections of the expected racial composition of all public schools in the district. The plan may include provision for cooperation with other school districts to assist in the correction of racial imbalance.