GENEVA – If Geneva School District 304 teachers strike, the administration has the option of keeping schools open with classes taught by substitutes, officials said.

Kane County Regional Superintendent Patricia Dal Santo said school administrators would need enough substitute teachers who were certified to teach core subjects of math, English, social studies and science and put in five hours of school.

Mary Fergus, a spokeswoman for the Illinois State Board of Education, said the school code defines a legal school day as one in which 50 percent or more of the district’s students are in attendance, based on the most recent month of full attendance before the work stoppage.