Neither of those answers are right because it was published in 1950. For works published in 1950 the copyright was 28 years, and if the copyright was renewed with the US Copyright Office they got another 67 years. This leaves two possibilities:

The copyright holder didn't renew, in which case the work already is (and has been for awhile) in the public domain.

The copyright holder did renew, and the copyright lasts until 2045.