Question $6$

The basic structure of a pipe$-$laying machine is shown below. The load carried at F is manoeuvred by means of two hydraulic rams CG and EB$.$ When the machine is lifting $8kN$ in the position shown find

$($a$)$ the thrust exerted by each of the rams and $($b$)$ the force on the pin at D$.$ Distances are as follows: $AB=BC=CD=2m.$

For this question how do you know which free body diagram to draw out when splitting the problem?