Which sentence shows a relationship between two independent clauses?

When Ruby gets hungry, she eats strawberries.
Leo loves to chase Lincoln around.
Ruby and Leo spent the day searching for butterflies and they also had a picnic in the park.
Although it was raining, Leo wanted to go outside.

Ruby and Leo spent the day searching for butterflies and they also had a picnic in the park.

The sentence that shows a relationship between two independent clauses is:

"Ruby and Leo spent the day searching for butterflies and they also had a picnic in the park.".