Broadly speaking, a B-1/B-2 would appear to be appropriate but U.S. Consulates oftentimes deny applications for such a visa even if it is the appropriate visa f

Broadly speaking, a B-1/B-2 would appear to be appropriate but U.S. Consulates oftentimes deny applications for such a visa even if it is the appropriate visa for other reasons (such as concerns about the applicant remaining in the U.S. or working without authorization) and the U.S. Consulates have a lot of discretion to deny such applications. You might want to look at the J-1 or even the H-2B or H-3 visa.