Which of the following would most likely increase the accuracy of estimating the project cost?

Using historical data.

Pricing out the work at lower levels in the work breakdown structure.

Both 1) Pricing out the work at lower levels in the work breakdown structure, and 2) Talking to people who have worked on similar projects.

Talking to people who have worked on similar projects.

1) Pricing out the work at lower levels in the work breakdown structure, and 2) Talking to people who have worked on similar projects, and 3) Using historical data.