Possible Clues:

• Mark's hat being worn by daughter
• What senor should have — daughter wearing hat
• Mark used four times in this puzzle's solution
• After reflection, change what's written about learner's Spanish mark
• It's displayed on some letters until December
• Mark over an 'n'
• Accent over an "n"
• Squiggle over Spanish n
• Symbol of equivalence, in math
• Style detail, a forgotten part of Sao Paulo, originally