We packed our food for a picnic at the park. Simple
Compound
Complex
Compound-Complex

Simple

Explanation:

The sentence isn't in multiple parts. "Simple" means a sentence with no commas ether. There's no commas, and it's not in multiple parts, so it's "simple".

and your question what topic are you in trouble with?

based on the graph, people who are asian/ pacific islander, are better at math than the other race/ethnicity's on the graph.