A contractor has been hired to conduct security reconnaissance on a company. The contractor browses the company's website to identify employees and then finds their Facebook pages. Posts found on Facebook indicate a favorite bar that employees frequently visit. The contractor visits the bar and learns details of the company's security infrastructure through small talk. What reconnaissance phase techniques does the contractor practice? $($Select all that apply.$)$

A$.$ Open Source Intelligence $($OSINT$)$

B$.$ Scanning

C$.$ Social engineering

D$.$ Persistence