SGMC polygons matching unit identifier CAgrpCA?;0

The shapefile could not be created.
pgsql2shp -f output/CAgrpCA?_0 -h igsaws910svrds1.er.usgs.gov -u emrt -P usgs -g wgs84_geom mrdata "select gid,state,unit_link,ref_id,generalize,src_url,'https://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit='||unit_link as url,wgs84_geom from sgmc2.geol_poly where unit_link='CAgrpCA?;0'"
Initializing...
Done (postgis major version: 3).
Output shape: Polygon
Dumping: X [1 rows].
zip -m CAgrpCA?_0.zip CAgrpCA?_0.*
updating: CAgrpCA3_0.zip (stored 0%)
updating: CAgrpCA?_0.cpg (stored 0%)
updating: CAgrpCA?_0.dbf (deflated 53%)
updating: CAgrpCA?_0.prj (deflated 40%)
updating: CAgrpCA?_0.shp (deflated 24%)
updating: CAgrpCA?_0.shx (deflated 45%)