A hinged beam structure is given in the Figure below. $3m,1m,1m,3m,$Find the influence lines for:

$($a$)$ The vertical support reaction at B

$($b$)$ The shear force at D

$($c$)$ The bending moment at D

$($d$)$ The most unfavourable position of the uniformly distributed load $(10$kN$/$m$)$ for the above

$($e$)$ The corresponding extreme values of the quantities for this distributed load.