Cluster size selection

Crystal manages operations for a meal delivery service in Houston, Texas. She has latitude and longitude data for meals requests in the past month. She'd like to create several new "delivery hubs" where demand has been greatest. In order to do this, she's asked a machine learning scientist to use a clustering algorithm to divide the orders into groups based on their location.

The machine learning scientist isn't sure how many clusters to make. Take a look at the clustering algorithm's results using different amount of clusters.

What is the most suitable number of clusters?