The Market Research Team of Shine,a Company Which Produces Hair

Multiple Choice

 The market research team of Shine,a company which produces hair products,is puzzled because their sale of hair shampoos has dropped drastically.The marketing manager is wondering if the drop in sales is a result of a recent newspaper article about deforestation caused by the company's extraction of palm oil for hair products.The manager wants to conduct a market research to see if the company needs to modify the product.He sends out a questionnaire by e-mail to their wide customer base to gather relevant information.Which of the following types of research methods is he using? 

A)  Observational research
B)  Experimental research
C)  Survey research
D)  Mathematical modeling research