Assertion: Flavr Savr is a genetically modified tomato which remains fresh for a long time
Reason: Production of polygalacturonase is blocked in FLAVR SAVR

The correct option is A Both assertion and reason are true and the reason is the correct explanation of the assertion

In tomatoes, enzyme polygalacturonase has the ability to dissolve cell wall component called pectin, which results in the softening of tomatoes. In Flavr Savr tomato, formation of polygalacturonase is inhibited which increases the shelf-life of the tomatoes. This was made so by adding an antisense gene which interferes with the production of the enzyme polygalacturonase. So both assertion and reason are true and the reason is a correct explanation of the assertion.