$1\mathrm{.}3.(4$ pts$)$ What are the equations of equilibrium? $($Select all that apply$)$

a$.$ Sum of applied loads $=0$

b$.$ Sum of moments $=0$

c$.$ Sum of $Fy=0$

d$.$ Sum of $Fx=0$

$1\mathrm{.}4.(4$ pts$)$ The area considered when calculating the load on a structural member is know as what?

a$.$ Zone of influence

b$.$ Tributary area

c$.$ Load factor

d$.$ Net section

$1\mathrm{.}5.(4$ pts$)$ Select the most economical section listed below that can support an ultimate axial compression load $($LRFD$)$ of $P=580$ kips. The section is pinned on both ends with an unbraced length of $19ft.$

a$.W1296$

b$.$ W$14$x$82$

c$.$ W$12$x$65$

d$.$ W$14$x$61$