Final answer:
The word 'but' is the correct option to complete the sentence in the given context.
Step-by-step explanation:
The correct answer is option 2) but. The sentence structure here is parallelism, where two contrasting ideas are presented using the conjunction 'but'. The first part of the sentence states that both applicants have experience in accounting, while the second part introduces the contrast that only one of them is familiar with the accounting software.
For example, if applicant A has experience in accounting but is not familiar with the accounting software, and applicant B also has experience in accounting but is familiar with the accounting software, then 'but' is the appropriate word to use to show the contrast between the two applicants.
Therefore, the correct sentence should be: 'The two applicants have experience in accounting, but only one is familiar with our accounting software.