The question asks for the most concise and clear statement.
Option (A) is long and wordy, using “may be an indication of solvency problems that will occur in the future,” which can be shortened to “may indicate future solvency problems.”
Option (B) is more concise but still uses “Modern industry’s history of marginal performance may indicate solvency problems in the future,” which is close to correct but “in the future” is redundant since “solvency problems” already implies future concern in context.
Option (C) is the most concise — it eliminates unnecessary clauses and repetition, and directly conveys the meaning without extra words. It also keeps the essential details: marginal performance, Modern Industry, and future solvency problems.
Option (D) includes the clause “which is marginal at best,” which adds nuance but makes the sentence slightly longer and less direct.
Thus, (C) is the correct choice for being both clear and concise.