Answer:

Introduction:
In the context of plant reproduction, there are two types of flowers: cleistogamous and chasmogamous. Cleistogamous flowers remain closed and self-fertilize, while chasmogamous flowers open and rely on external factors such as pollinators for fertilization.

Explanation of Statements:

a) Cleistogamous flowers always exhibit autogamy.
Cleistogamous flowers are self-pollinating flowers that remain closed. This means that the pollen from the anther of the flower is transferred directly to the stigma of the same flower. Hence, statement a) is correct.

b) Chasmogamous flowers always exhibit geitonogamy.
Chasmogamous flowers are open flowers that rely on external factors such as wind or pollinators for fertilization. Geitonogamy refers to the transfer of pollen from the anther of one flower to the stigma of another flower on the same plant. While chasmogamous flowers can exhibit geitonogamy, they can also undergo cross-pollination, where the pollen is transferred to the stigma of a different plant. Hence, statement b) is incorrect.

c) Cleistogamous flowers exhibit both autogamy and geitonogamy.
Cleistogamous flowers are self-pollinating flowers that remain closed, which means they exhibit autogamy. However, since they do not rely on external factors for pollination, they do not exhibit geitonogamy. Hence, statement c) is incorrect.

d) Chasmogamous flowers never exhibit autogamy.
Chasmogamous flowers are open flowers that rely on external factors for fertilization. These flowers are designed for cross-pollination, which involves the transfer of pollen from the anther of one flower to the stigma of a different flower. Autogamy refers to self-pollination, which is not favored in chasmogamous flowers. Therefore, statement d) is correct.

Summary:
The correct statement from the given options is:
d) Chasmogamous flowers never exhibit autogamy.

Cleistogamous flowers always exhibit autogamy, but they do not exhibit geitonogamy. Chasmogamous flowers can exhibit geitonogamy, but they do not exhibit autogamy.

Option..(a) because autogamy states self pollination....and cliestogamy generally pollinated in closed flower which completely follow self pollination.