Right answer: tos
Usually, when you have a cold (resfriado in spanish) you feel tired, with fever, nasal congestion with sneezing. Also, it is possible that there is a sore throat, headache, cough, among other symptoms.
The spanish word for cough is tos. So, in this context the correct option is tos and the complete sentence is:
Ella tiene un resfriado y tiene tos
She has a cold and has a cough
