Discuss the appropriateness of the manufacturing overhead application base used in each of the following examples.

Required
a. Barlowe Manufacturing produces cell phone covers. The manufacturing process is highly automated, requiring very little human contact. The company uses direct labor hours as its manufacturing overhead application base.
b. Sky High Tumblers manufactures tumbling mats. Although part of the production process is automated, significant human effort is required to complete the mats. The company uses machine hours as its manufacturing overhead application base.
c. Hill, Hill, and Dale is a dental office that performs a variety of dental services for its patients. For most services, the dental hygienists spend much more time with the patients than the dentists do. The company uses direct labor dollars as its overhead application base.0
d. Lamberti Industries is a leading manufacturer of perfumes. The entire mixing process for the perfumes is automated and controlled by highly sensitive computers. The company uses machine hours as its manufacturing overhead application base.