单项选择题

Directions: After reading the following passage, you will find 5 questions or unfinished statements. For each question or statement there are 4 choices marked A, B, C and D.
Many jobs have been lost and they may not be coming back. Some occupations had already been declining for years due to advances in technology and changes in the global economy. The following is a list of careers that are disappearing.
Stage Performers
The five-year decline for this career was a surprising 61%. Stage performances have fallen out of fashion and have been almost entirely replaced with movies and home entertainment technologies.
Postal Service Mail Sorters (分拣员)
After losing almost 57000 jobs between 2004 and 2009, a further 30% decline in this occupation can be seen by 2018. With more automatic processes for mail sorting and increasing correspondence via e-mail and fax, this job is quickly becoming unnecessary.
Office Support Workers
About 300000 office support jobs disappeared between 2004 and 2009. Secretaries and file clerks are no longer in demand as companies cut costs. Moreover, technologies like voicemail and easy-to-use word processors have enabled professionals to do their own office work.
Photo Processors
With the rise of digital photography and automatic printing, positions for manual photo printers are rapidly disappearing. The occupation has been steadily losing jobs in the last five years and there might be a 24% decline by 2018.
Radio Operators
As technology advances, the need for workers to monitor communications via radiotelephone equipment is disappearing. This already small field saw a five-year decline of 43%. One reason why the career of stage performers is declining so fast is that ______.