(1) is no help in finding the first term of S --- INSUFF

For example, the following sequences each have 4 as their third term, yet they have different first terms:

0, 2, 4

-4, 0, 4

This eliminates choices A and D.

Although (2) contains a lot of information, it also is not sufficient. For example, the following sequences each satisfy (2),

yet they have different first terms:

1, 3, 12

3, 9, 36

This eliminates B.

Next, we consider (1) and (2) together. From (1), we know "the 3rd term of S is 4." From (2), we know "the 3rd term is four times the 2nd." This is equivalent to saying the 2nd term is 1/4 the 3rd term: (1/4)4 = 1. Further, from (2), we know "the 2nd term is three times the 1st." This is equivalent to saying the 1st term is 1/3 the 2nd term: (1/3)1 = 1/3. Hence, the first term of the sequence is fully determined: 1/3, 1, 4.

The answer is C.
Vivek.

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