Professor Very Busy Needs to Allocate Time Next Week to Include

Multiple Choice

Professor Very Busy needs to allocate time next week to include time for office hours. He needs to forecast the number of students who will seek appointments. He has gathered the following data:
What is this week's forecast using exponential smoothing with alpha = .2, if the forecast for two weeks ago was 90?

A)  49
B)  50
C)  52
D)  65
E)  78