Consider the pin-jointed plane truss shown in the figure $\text{(not drawn to scale)}$.Let $R_{P}, R_{Q}$ and $R_{R}$ denote the vertical reactions (upward positive) applied by the supports at $P, Q$ and $R,$ respectively , on the truss. The correct combination of $(R_{P},R_{Q},R_{R})$ is represented by

1. $\text{(30,-30,30)kN}$
2. $\text{(20,0,10)kN}$
3. $\text{(10,30,-10)kN}$
4. $\text{(0,60,-30)kN}$