Hard choice between B and C. I would go with C, because the term "long time" is quite flexible. "Develop significant weaknesses" is already mentioned in the statement and reflects the overall conclusion accurately.
(B) It would be irresponsible to postpone changes to the vendor contracts just because the supply chain will not develop weaknesses fora long time .
(C) lf no changes are made to the vendor contracts, the supply chain will eventually develop significant weaknesses
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(B) It would be irresponsible to postpone changes to the vendor contracts just because the supply chain will not develop weaknesses fora long time .
(C) lf no changes are made to the vendor contracts, the supply chain will eventually develop significant weaknesses
...
