Final answer:
The correct conjunction to complete the sentence is 'pero', which means 'but' in English.
Step-by-step explanation:
The correct conjunction to complete the sentence is 'pero'. 'Pero' means 'but' in English and is used to connect two contrasting ideas. In this case, it connects the fact that the dry cleaner is open with the reason the person is unable to leave their clothes today. The complete sentence would be: 'La tintoreria está abierta, pero hoy no tengo tiempo para dejar la ropa. La llevaré mañana.' (The dry cleaner is open, but I don't have time to drop off the clothes today. I will take them tomorrow.)
Learn more about Conjunctions in Spanish