You will be given three variants of annotations to the text "Father of the Periodic table". Study the annotations carefullty. Choose the one that best reflects the content of the text and corresponds to the rules and norms of writing of annotatikon.

You will be given three variants of annotations to the text "Father of the Periodic table". Study the annotations carefullty. Choose the one that best reflects the content of the text and corresponds to the rules and norms of writing of annotatikon.

Выберите один ответ:

• a. Dmitri Mendeleev was a famous Russian chemist and inventor. He is known for his invention of the Periodic table of elements. He also wrote a chemistry textbook, titled “Principles of Chemistry”. While working on the textbook, he had a dream. When he woke up he wrote down the ideas he had in his dream. That was the ideas about the systematic arrangements of the elements according to their atomic weight and valence. He presented his findings to the Russian Chemical Society and published them in the scientific journal.
• b. Dmitri Mendeleev, a Russian chemist and inventor, is considered the "father" of the periodic table. Since there were no modern organic chemistry textbooks in Russian at that time, Mendeleev decided to write one, and simultaneously tackle the problem of the disordered elements. Mendeleev wrote the definitive chemistry textbook of his time, titled "Principles of Chemistry" (two volumes, 1868–1870). After intensely working on this "puzzle" for three days, Mendeleev said that he had a dream in which all of the elements fell into place as required. Mendeleev arranged the elements according to both atomic weight and valence. Not only did he leave space for elements not yet discovered, but he predicted the properties of five of these elements and their compounds. In 1869, he presented the findings to the Russian Chemical Society.
• c. The text deals with the history of creation of the periodic table. It traces back to the facts of the work conducted by D.I. Mendeleev and highlights the difficulties he faced. The texts gives valuable information on the basis and laws that underpin the principles according to which the elements are arranged into the table. It draws our attention to the fact that the table allowed to predict the properties of the elements that had not been discovered yet. The main idea of the text is to show the significance and importance of Mendeleev’s discovery. The text may be of the interest to a wide range of people.