Jack struggled with the shifts in temperature the frosty air of the early morning became a baking heat by midday.
Which revision corrects the run-on sentence?
O 1. Jack struggled with the shifts in temperature, the frosty air of the early morning became a baking heat by midday.
2. Jack struggled with the shifts in temperature; the frosty air of the early morning became a baking heat by midday.
03. Jack struggled with the shifts in temperature but the frosty air of the early morning became a baking heat by midday.
4. Jack struggled with the shifts in temperature and the frosty air of the early morning became a baking heat by midday.