下列逻辑表达式，值为false的是()。 A: "abc,,,bcd,,def,efg,,".split("[,]+").length == 4; B: "1st456".matches("\\d[a-z&&[^et]]{2,8}[0-9]+"); C: "abcdefghijklmnopqrstuvwxyz".substring(5,26).length() == 20; D: "whatisjava".equals(null);