Three concrete stress$-$strain curves $($i$.$e$.,$ Curves A$,$ B$,$ and C$)$ are presented in Fig. $1.($a$)(3$ points$)$ Determine for each curve, the $($approximate$)$ specified compressive strength and strain of the concrete.$($b$)(1$ point$)$ Per appropriate ACI$318-14/19$ equations or expressions, find the modulus of elasticity $($Ec$)$ of concrete Curve B shown in Fig. $1.$ Assume normal weight concrete.$($c$)(2$ points$)$ Using Secant approach, find the Secant modulus of elasticity of concrete Curve B shown in Fig. $1.($d$)(1$ point$)$ Per appropriate ACI$318-14/19$ equations or expressions, determine the modulus of rupture $($fr$)$ of concrete Curve C shown in Fig. $1.$ Assume normal weight concrete.$($e$)(1$ point$)$ Would the answer for part $($d$)$ be different if the concrete were classified as sand$-$lightweight concrete. If yes, what would be the corresponding