An App That Performs Synchronous Tasks on a Single-Core Computer

An app that performs synchronous tasks on a single-core computer often takes longer to execute than on a multi-core computer,because ________.

A) it's too costly to convert them to asynchronous tasks
B) the processor is shared between the app and all the others that happen to be executing on the computer at the same time
C) multi-core computers have no overhead
D) single-core compters generally have slower processors