https://reverb.com/blog/crazy-hard-guitar-trivia

And the answer is ...
 
Wood!
 
hehehehe
 
Bill, tgo

According to the long story ...
 
During 1969 we developed the Alembic electronics and pickups. We first installed them in David Crosby's 12-string Guild guitar (which he still uses to this day) and then into Phil Lesh's SG bass that had been hand painted by Bob Thomas in his trademark renaissance/psychedelic style. After several more experimental designs, both Phil Lesh's and Jack Casady's hollow-bodied Guild basses were renovated with new low-impedance pickups and new active electronics. Bobby Weir's and Jerry Garcia's guitars were done as well.
 
The quiz is asking about basses, so Crosby's guitar doesn't count.  Next would be Lesh's hand painted Gibson, but the quiz uses the word batch, which would tend to suggest several; so I'm guessing the Gibson doesn't count either.  That leaves the Guilds as the closest of the four choices in the quiz.