It seems like in order to generate a C9H10 product after the tert-butanol elimination the Bromine that's added initially couldn't be on the any of the aromatic ring carbons, which inclines me to belive that answer A is correct. However, I have no idea why any of these answers wouldn't have multiple possible bromination locations, so I don't have any idea which one satisfies the criterium that it would only generate one C9H11Br intermediate. If someone can indicate the correct answer and also explain why it would generate only one the C9H11Br product and how it undergoes the second reaction to generate C9H10 that'd be great!
EXPLAIN