Which of the following is/are referred to by the term 'tool'?

Directions: Read the following passage carefully and answer the given question:

The learning of a foreign language should be an integral part of every university student's education. As a discipline, it affords the mind excellent training. It utilises skills needed in so many other subjects: the concentration required for memorising music (not to mention developing the ear for tone and pitch). The logical thinking for resolving mathematical problems, even the deductive reasoning capabilities needed to comprehend philosophical concepts. The mind is stretched through the simple act of teaming the grammatical patterns, vocabulary and phonological system of a language. At the same time, the student of a foreign language is acquiring a useful tool. This tool has a double advantage. For, while most people (especially teachers) expound on the rewards of being able to communicate in a second, third or fourth language, perhaps the more promising of the two, is being able to understand and hopefully appreciate another cultural group through their literature, their music and customs all of which are best assimilated through the medium of their language.