An abstract class can
a) implement an interface
b) extend another abstract class
c) extend another regular class
d) a and b
e) a and c

Consider the series where in this problem you must attempt to use the ratio test to decide whether the series converges. compute enter the numerical value of the limit l if it converges, inf if it diverges to infinity, minf if it diverges to negative infinity, or div if it diverges but not to infinity or negative infinity.