The two statements in question are related to specific stages of meiosis, specifically prophase I. Understanding these stages will help us decide the accuracy of the statements.

Statement I: Chromosomes become gradually visible under light microscope during leptotene stage.

Analysis of Statement I: During the leptotene stage of prophase I in meiosis, chromatin begins to condense, making chromosomes more visible under the light microscope. However, it is important to note that the chromosomes are not fully condensed at this stage. They continue condensing in the later stages (zygotene and pachytene). Therefore, the statement is largely accurate as it reflects the initial visibility of the chromosomes.

Statement II: The beginning of diplotene stage is recognized by dissolution of synaptonemal complex.

Analysis of Statement II: In the diplotene stage of prophase I, the previously formed synaptonemal complexes, which assist in the pairing of homologous chromosomes during the earlier zygotene and pachytene stages, start to dissolve. This dissolution marks the transition into diplotene and is a key event that defines this stage. So, this statement is true.

Given that the analysis shows both statements to be accurate in their description of events during meiosis, the most appropriate choice is:

Option A: Both Statement I and Statement II are true.