Read the passage given below and then answer the questions given below the passage. Some words may be highlighted for your attention. Read carefully.

Music can be divided into genres (e.g., country music) and genres can be further divided into subgenres (e.g., country blues and pop country are two of the many country subgenres), although the dividing lines and relationships between music genres are often subtle, sometimes open to personal interpretation, and occasionally controversial. For example, it can be hard to draw the line between some early 1980s hard rock and heavy metal. Within the arts, music may be classified as performing art, fine art, or auditory art. Music may be played or sung and heard live at a rock concert or orchestra performance, heard live as part of a dramatic work (a music theater show or opera), or it may be recorded and listened to on a radio, MP3 player, CD player, smartphone or as film score or TV show.

By bringing music to the classrooms, schools are doing an important job by encouraging children to sing or play an instrument, thereby giving them a gift that will last for a lifetime. Students of music are better suited to face the world once they leave school. Here is what Jo-Ann Hood, Music Teacher, Nashville Forum, has to say about the impact of music on children. “I have found, during my 18 years of teaching, that music students tend to score better on tests, have better communication skills, and are better-disciplined students. They tend to be more prepared for the workforce and are more readily hired by businesses. I have also seen several instances where music kept a student in school who would have otherwise dropped out.” Learning music at a young age can also equip people with skills that will benefit them when they grow old. John Ratey, MD, in his book titled "The User's Guide to the Brain,” talks about how music benefits elders by helping the brain organize information and allow for self-expression. Even Albert Einstein, the renowned physicist who learned to play the violin and piano in his childhood, continued to play and enjoy music till his very last days, commenting that he got most of his joy in life out of music.

Which of the following words are the synonyms of the word subtle highlighted in the passage?