Mendel obtained a true breeding line of Pisum sativum through continuous :
cross-pollination
Self-pollination
None of them
Self-pollination of F2.
As we have discussed in Gregor Johann Mendel- Father of Genetics -
Mendel conducted such artificial pollination/cross-pollination experiments using several true-breeding pea lines. A true- breeding line is one that, having undergone continuous self-pollination, shows the stable trait inheritance and expression for several generations. Hence, the correct option is (b).