Following are selected financial statement data from $3$M Company. Required a$.$ Compute the return on assets $($ROA$),$ profit margin $($PM$),$ and asset turnover $($AT$)$ for each of the three years F$2,$ F$3,$ and F$4.$ Round any intermediate calculations to the nearest whole dollar amount. b$.$ What factor is mainly responsible for the change in $3$M$\text{'}$s ROA from FY$2$ to FY$3?$ Is it profit margin or asset turnover or both? c$.$ What factor is $**$mainly$*$ responsible for the change in $3$M$\text{'}$s ROA from FY$3$ to FY$4?$ Is it profit margin or asset turnover or both?