A former student-teacher at a Sussex County elementary school would be sentenced to four years in prison if she pleads guilty to having sexual relations with one of her students, under a plea bargain offer made today. Lindsay Massaro, 25, was given until Feb. 14 to accept the offer, which would require her to plead guilty to one count of second-degree sexual assault. Superior Court Judge N. Peter Conforti, sitting in Newton, told Massaro that she could face up to 46½ years in prison if she is convicted of all of the six charges against her, including first-degree aggravated assault....