With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: In December 1962, the Beatles concluded their fifth and final Hamburg residency. By 1963, they had agreed that all four band members would contribute vocals to their albums – including Starr, despite his restricted vocal range, to validate his standing in the group. Lennon and McCartney had established a songwriting partnership, and as the band's success grew, their dominant collaboration limited Harrison's opportunities as a lead vocalist. Epstein, to maximise the Beatles' commercial potential, encouraged them to adopt a professional approach to performing. Lennon recalled him saying, "Look, if you really want to get in these bigger places, you're going to have to change – stop eating on stage, stop swearing, stop smoking..." Lennon said: "We used to dress how we liked, on and off stage. He'd tell us that jeans were not particularly smart and could we possibly manage to wear proper trousers, but he didn't want us suddenly looking square. He'd let us have our own sense of individuality."
text_B: Do people generally sing at their best when eating?
NO.