Choose the right grammatical form in each gap to complete the dialogue.

This is a story about two girls. They are sisters. The older [girl|girls'|girl's] name is Carol. Her [sister|sister's|sisters'] name is Jessica. [Carol and Jessica's|Carol's and Jessica's|Carol and Jessica] grandparents live in another neighbourhood. Their [grandparents's|grandparents'|grandparents] names are Paul and Mary. Girls visit them every weekend. This week girls will do the same. They will take [their|they|her] bicycles and ride there. The trip usually takes \(15\) minutes. Every time they arrive to their grandparents [she|they|their] have tea with cookies and then go for a walk.