In a high school, a class teacher is scheduling the six subjects into periods 1 through 6 for her class. The subjects are: Hindi, English, Mathematics, Science, History and Geography. She has to abide by the following conditions:

History has to be immediately after Geography.

Science has to be earlier than History.

English has to be earlier than Mathematics.

English has to be either immediately before or immediately after Hindi.

If the Mathematics period is scheduled before Science, then Geography must be which period?