निम्नलिखित में से कौन-सा एक प्राकृतिक खाद्य संरक्षक (Food Preservative) है?

Which statement correctly identifies the primary preservation principle in preparing jams and jellies? I. Preservation is primarily due to adding pectin. II. Preservation is primarily due to strict freezing temperatures. III. Preservation is primarily due to adding citric acid. IV. Preservation is primarily due to high sugar concentration creating osmotic pressure.

Given below are two statements regarding food preservation, one labeled as Assertion (A) and the other as Reason (R): Assertion (A): Vinegar is used as the sole preservative for making all types of regional pickles. Reason (R): Vinegar (acetic acid) acts as an effective antimicrobial preservative in products like tomato sauce and ketchup.