In gametophytic self-incompatibility system, when sib-matings are carried out, the crosses are

Correct option is C

✅ (c) Fully compatible, partially compatible or fully incompatible [Variable Fertility] • In the gametophytic self-incompatibility (GSI) system, compatibility is determined by the haploid genotype of the pollen. • Sib matings (between individuals from the same family) may share alleles, leading to: • Full compatibility (no shared alleles) • Partial compatibility (one shared allele) • Full incompatibility (both alleles shared) • Found in crops like tobacco, tomato, and petunia.
❌ (a) Fully compatible or partially compatible • Incorrect because full incompatibility is also a possibility in GSI.
❌ (b) Always partially compatible • Overgeneralization — all three compatibility outcomes are possible.
❌ (d) Always fully compatible • This is only possible in sporophytic systems under specific conditions.