Answer
Please see the work below.
Work Step by Step
a. we know that burning lithium metal in oxygen reaction is given as
$4Li+O_2\rightarrow 2Li_2O$
b. Organic materials burn in oxygen and the reaction is given as
$4CH_3NH_2+9O_2\rightarrow 4CO_2+2N_2+10H_2O$
c. Combustion reaction for diethyl sulfide is given as
$2(C_2H_5)_2+15O_2\rightarrow 8CO_2+10H_2O+2SO_2$
