Look at the Assertion on its own first. It says a charitable trust tried to escape Section 25-F retrenchment protection by arguing it is not an "industry" under Section 2(j), after sacking a Safai Karamchari for repeated absence. That is simply a factual account of a genuine and frequently seen defence raised by charitable and religious bodies, so there is nothing false in it, it is true.
Now look at the Reason by itself, setting the Assertion aside. It tells us the trust ran several kinds of activity, some commercial, alongside its charitable work, and that it employed people in an organised way with regular pay. Nothing here is disputed or implausible, it is a straightforward description of an organisation functioning on a reasonably large and systematic scale, so the Reason too stands as true.
The real question is whether the Reason actually explains the Assertion, or whether the two are just true statements sitting side by side. The law on "industry" has long moved past looking at motive or charitable purpose alone, the focus is on whether the operation is systematic, cooperative between employer and workers, and geared towards producing goods or services. A body that runs organised commercial ventures and hires paid staff meets exactly that description, and once it does, it cannot claim exemption merely by calling itself charitable. That is precisely why the trust's argument in the Assertion would not succeed, the very facts in the Reason are what defeat it. So the link is not a coincidence, the Reason is the working cause behind the outcome described in the Assertion.
Since both statements hold up independently and the second is shown to directly account for the first, the composite answer follows without needing any other option.
\[ \boxed{\text{Both (A) and (R) are true, and (R) is the correct explanation of (A).}} \]