Use the Data Given Below to Answer the Following Question(s)

Multiple Choice

Use the data given below to answer the following question(s) .
The table provided below gives the sales details of the number of android smart phones at an electronic retail store for the past 6 weeks. The time series appears to be relatively stable, without trend, seasonal, or cyclical effects. (Hint: Optimize α value in 0.1 increments) $$\begin{array} { | c | c | } \hline \text { Week } & \text { Units sold } \\\hline 1 & 88 \\\hline 2 & 44 \\\hline 3 & 54 \\\hline 4 & 65 \\\hline 5 & 72 \\\hline 6 & 85 \\\hline\end{array}$$
-What is the formula used to calculate the value of at in the linear trend equation Ft+k = at + btk while using double exponential smoothing?

A) at = ?(bt - bt-1) + (1 -?) bt-1
B) at = ?Ft-1 + (1 - ?) (at +1 + bt+1)
C) at = ?Ft + (1 - ?) (at -1 + bt-1)
D) at = ?(bt + bt-1) + (1 + ?) bt-1