The half-life of Calcium-47 is 3.91 x 10^5 seconds. A sample contains 4.11 x 10^16 nuclei. What is the decay constant for this decay?

a) 2.75 x 10^-6 s-1

b) 3.46 x 10^-6 s-1

c) 1.77 x 10^-6 s-1

d) 3.37 x 10^-6 s-1