Seed viability is being tested by:

Correct option is A

✅ (a) Tetrazolium test: • A biochemical test for assessing seed viability quickly. • Based on dehydrogenase enzyme activity, which reduces TTC to a red-colored compound in living tissues. • Gives results in hours, unlike germination tests.
❌ (b) First count test: • A part of standard germination test; doesn't specifically test viability.
❌ (c) Grow out test: • Used to test genetic purity, not seed viability.
❌ (d) None of them: • Incorrect as Tetrazolium test is a standard method.