The correct answer is 4- share of shelf- if she is interested in capturing distribution metrics she should be in a position to check whether she is getting the share of shelf she deserves so as there is maximum distribution. There are different methods she can use to measure share of shelf which are facings calculation and measuring of the shelf once she knows the share of shelf it can help in capturing distribution metrics. She will compare her brand`s facing to the total facings positions that are available and determine whether they will capture her distribution metrics. Customer complaints, effective reach and trial rate are time consuming as customers may take time to complain hence her distribution will be low. There is waiting time as compared to share of shelf where she can do calculations immediately.