Answer:
May it's the month closest to the sales on January.
Step-by-step explanation:
When the sales number of each month are calculated with the variance indicated, the sales that are similar to that on January are the May's sales.
Please see the details below:
Jan : $100
Feb : $110 (+10%)
March: $94 (-15%)
April : $112 (+20%)
May: $101 ( -10%)
Jun: $106 (+ 5%)