81, 27, 9, 3,...
arithmetic, 0, -3, -6
geometric, 0, -3, -6
geometric, 1, 1 1 39
The sequence is neither geometric nor arithmetic.
AAAaannndd the bot gets it wrong yet again!
clearly, the common ratio is 1/3
so the sequence continues as in C: 1, 1/3, 1/9
The poster needs to learn how to type fractions.