take latest enterprise installer:
mongodb-win32-x86_64-enterprise-windows-64-3.4.5-signed

run installer, go to custom, change the installation path, start installation

installer installs into c:

i did it twice, once without the existing path on D, once with existing path on D
it never did install into D drive but always to C drive
select a different installation path in installer (drive)
installer will still install into default path