In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.
Q: Question: The organometallic compounds are derivatives:
Options: <0> With a radical nature. <1> With covalent bonds between carbon atoms and metal atoms. <2> With electronic deficit and electrophilic character. <3> Practically not reactive. <4> With essentially reducing character.
A:
pharmacology