I am totally lost... need some HELP...

Classify each of the series as absolutely convergent,

conditionally convergent, or divergent.

a) (Sigma n=1..inf) (4^2n)/((-5)^n)

b) (Sigma n=1..inf) sin(1/n^1/2)

c) (Sigma n=1..inf) (-1)^n-1(2^3n)/(n^n)

please help... im not thorough with sequences and series at all..

zee