The table below shows the functions to represent the sale f(t), in thousands, of four companies in t years: company a b c d sale f(t) = 1.05t f(t) = 0.75t f(t) = 1.2^12t f(t) = 0.97^12t which of the following companies showed an exponential decay in sale? company a and company c company b and company d company c and company d company a and company b

Correct Company B and D

The exponential function decays if the base of the function is less than 1. 

The given functions are:

Company A: 
Company B: 
Company C: 
Company D: 

The bases of functions B and D are less than 1 and the bases of functions A and C are larger than 1. So this mean, sales of company B and D are decaying and sales of company A and C are growing.

None of the options you showed are it.