on whiCh oF thE Following Assumptions is BAsED thE BEliEF, thAt trEE-ring thiCknEssEs show links BEtwEEn solAr pErioDiCity AnD tErrEstriAl ClimAtE
A．solAr-ACtivity CyClE ExistED m its prEsEnt Form During thE pErioD in quEstion.
B．AvErAgE trEE-ring thiCknEss vAriEs From spECiEs to spECiEs.
C．trEE-ring thiCknEss vAriEs with ChAngEs in tErrEstriAl ClimAtE.
D．Both tErrEstriAl ClimAtE AnD solAr-ACtivity CyClE rAnDomly AFFECt trEE-ring thiCknEss.