"A situation where demand for a product exceed supply"-Please choose the correct one from the following.

It is (E) non of the above. The situation where demand exceeds supply is called EXCESS DEMAND.

Demarketing is the EFFORTS that are made to decrease the market demand when it exceeds supply, 

I my opinion, the option E is valid in the above mentioned situation.However, both De-marketing and synchronized marketing are somewhat familiar with the situation but not a proper match with the situation.

A. De marketing

That's Shortages. Thanks.

De-marketing:The process of reducing the demand for a product or decreasing consumption. Marketing aimed at limiting market growth; for example, some governments practice de-marketing to conserve natural resources and organizations use a de-marketing approach when there is so much demand that they are unable to serve the needs of all potential customers adequately. 

A case in point would be the example of IPCL (Indian Petrochemicals Corporation Limited) which de-markets its own product saying “Save Oil Save India”.

The answer is E (non of the options stated)

A.DE marketing

although de-marketing is the closest yet it doesn't answer the question. hence the answer would be E. None Of These. 

Synchronized Marketing

Always "Synchronized Marketing"

demarketing

Efforts aimed at discouraging (not destroying) the demand for a product which (1) a firm cannot supply in large-enough quantities, or (2) does not want to supply in a certain region where the high costs of distribution or promotion allow only a too little profit margin. Common demarketing strategies include higher prices, scaled-down advertising, and product redesign.