Answer : The correct option is, (A) uses of functional groups involving oxygen.
Explanation :
(1) 
 : It belongs to an alcoholic functional group in which the the
 : It belongs to an alcoholic functional group in which the the 
 group is directly attached to the alkyl group of carbon.
 group is directly attached to the alkyl group of carbon.
(2) 
 : It belongs to an ether functional group in which the the oxygen is directly attached to the two alkyl group of carbon.
 : It belongs to an ether functional group in which the the oxygen is directly attached to the two alkyl group of carbon.
(3) 
 : It belongs to ketone functional group in which the the
 : It belongs to ketone functional group in which the the 
 group is directly attached to the two alkyl group of carbon.
 group is directly attached to the two alkyl group of carbon.
(4) 
 : It belongs to an aldehyde functional group in which the the
 : It belongs to an aldehyde functional group in which the the 
 group is directly attached to the alkyl group of carbon.
 group is directly attached to the alkyl group of carbon.
(5) 
 : It belongs to carboxylic acid functional group in which the the
 : It belongs to carboxylic acid functional group in which the the 
 group is directly attached to the alkyl group of carbon.
 group is directly attached to the alkyl group of carbon.
(6) 
 : It belongs to ester functional group in which the the
 : It belongs to ester functional group in which the the 
 group is directly attached to the two alkyl group of carbon.
 group is directly attached to the two alkyl group of carbon.
 : It belongs to an amine functional group in which the the
 : It belongs to an amine functional group in which the the 
 group is directly attached to the alkyl group of carbon.
 group is directly attached to the alkyl group of carbon.
 : It belongs to halide functional group in which the the
 : It belongs to halide functional group in which the the 
 group (all the halogens) is directly attached to the alkyl group of carbon.
 group (all the halogens) is directly attached to the alkyl group of carbon.
From the above and from the question we conclude that, some uses of functional groups are given in which the an oxygen are present in all the functional groups.
Hence, the correct option is, (A) uses of functional groups involving oxygen.