GRE General Test: RC-233859 GRE Reading Comprehension

The painter Peter Brandon never dated his works, and their chronology is only now beginning to take shape in the critical literature. A recent dating of a Brandon self-portrait to 1930 is surely wrong. Brandon was 63 years old in 1930, yet the painting shows a young, dark-haired man-obviously Brandon, but clearly not a man of 63.
Which of the following, if justifiably assumed, allows the conclusion to be properly drawn?