Identify the functional groups in the following compounds

The functional groups present in the given compounds are:

(a) Aldehyde (–CHO),

Hydroxyl(–OH), 

Methoxy (–OMe),

$\mathrm{C}=\mathrm{C}$ double bond $(-\stackrel{1}{\mathrm{C}}=\stackrel{1}{\mathrm{C}}-)$

(b) Amino (–NH2); primary amine,

Ester (-O-CO-), 

Triethylamine (N(C2H5)2); tertiary amine

(c) Nitro (–NO2),

$\mathrm{C}=\mathrm{C}$ double bond $(-\mathrm{C}=\mathrm{C}-)$