Final answer:
The geometric sequences in the options are a) 3, 12, 48, ... and c) 0, 1, 3, 9, ...
Step-by-step explanation:
A geometric sequence is a sequence where each term is found by multiplying the previous term by a constant ratio. Let's analyze each option:
a) 3, 12, 48, . . . In this sequence, each term is obtained by multiplying the previous term by 4. So, this is a geometric sequence.
b) 3, 1, . . . This sequence does not have a consistent ratio between terms. So, it is not a geometric sequence.
c) 0, 1, 3, 9, . . . In this sequence, each term is obtained by multiplying the previous term by 3. So, this is a geometric sequence.
d) 3, 6, 12, 21, . . . This sequence does not have a consistent ratio between terms. So, it is not a geometric sequence.
Therefore, the geometric sequences are options a) and c).