My Aunt (1)/ was first (2)/ to gel a degree. (3)/ No error (4)

Answer

2

Explanation

the will be used before first because
- the (Def. Art.) is used before Ordinal numbers.
Look at the examples given below:
This is the first time I.ve ridden a horse.
Their team won the second prize for the Quiz Com- petition.
Hence, was the first Is the right usage