ACI Code $24\mathrm{.}5\mathrm{.}2$ defines three classifications of behavior of prestressed concrete, as shown below: $U,T$ and C classes. Discuss briefly what class is more suitable for economics but may be a more risky design. Also, explain why. $(5$pt$)$

TABLE $22\mathrm{.}1$

Permissible calculated stresses in concrete in prestressed flexural members

$\backslash$table$[[$Condition$,$Class$],[$U$,$T$,C^{***}$