A teacher shall lose seniority for any of the following reasons:
A. The teacher resigns.
B. The teacher has been laid off by this School Board and becomes employed full time under a Teacher-General Contract in another School Division
C. The teacher fails to return to work after termination of any leave granted by the Board.
D. The teacher is not re-employed within twelve (12) months following the date of lay-off.
E. The teacher's contract is terminated for cause.
F. The teacher fails to comply with paragraph 20.09.