In which one of the following, both autogamy and geitonogamy are prevented?

Given below are two statements:
Statement $I$: In heteromorphic flowers,pollen grains produced from anther pollinate stigmas produced at same level.
Statement $II$: In Tobacco,the germination of pollen on the stigma of the same flower is inhibited.
In the light of above statements,select the correct option given below:

Mention two strategies evolved to prevent self-pollination in flowers.

Unisexuality of flowers prevents

In monoecious plants like castor and maize:

List three strategies that a bisexual chasmogamous flower can evolve to prevent self-pollination (autogamy).