Which is the correct option to complete this paragraph from an article on Managing Multicultural Teams?

When a major international software developer needed a new product quickly, the project manager assembled a team of employees from India and the United States. From the start the team members could on a delivery date for the product. The Americans thought the work could be done in two weeks; the Indians predicted two to three months. As time went on, the Indian team members proved reluctant setbacks in the production process, which the American team members would find out about only when work was due to be passed to them.

(Adapted trom https://hbr.org/2006/11/managing-multicultural-teams)