The given sequence is 4,12,36,108....
Here we can observe the first term [tex] a_{1} [/tex] = 4 , [tex] a_{2}=12 [/tex] and so on.
The common ratio (r)=[tex] \frac{12}{4}=3 [/tex]
Since the common ratio is greater than 1,
Therefore the sum of the geometric series = [tex] \frac{a(r^{n}-1)}{r-1} [/tex]
Since we have to find the sum of first seven terms, so n=7
=[tex] \frac{4(3^{7}-1)}{3-1} [/tex]
=4372.
Therefore, option C is the correct answer.
