"The emancipation of women", James Joyce told one of his friends, "has caused the greatest revolution in our time."
Other modernists agree: Virginia Woolf, claiming that in about 1910 "human character changed" and illustrating the new balance between the sexes, urged, "Read the 'Agamemnon' and see whether your sympathies are not almost entirely with Clytemnestra". D.H. Lawrence wrote "perhaps the deepest fight for 200 years and more has been the fight for women's independence".
But if modernist writers considered women's revolt against men's domination as one of their "greatest" and "deepest" themes, only recently, perhaps in the past 15 years has literary criticism begun to catch up with it. Not that the images of sexual antagonism that abound in modern literature have gone unremarked - far from it. We are able to see in literary works the perspective we bring to them and now that women are enough to make a difference in reforming canons and interpreting literature, the landscapes of literary history and the features of individual books have begun to change.
The author's attitude towards women's reformation of literary canons can best be described as one of:
A quick way to judge an author's attitude is to check whether the language used to describe an idea is neutral, critical or approving. Here the closing lines describe women reforming literary canons and reinterpreting old texts in a way that reads as natural progress, framed as something that had been waiting to happen once women are enough in number to drive it.
Check the other choices against that tone. Ambivalence would require some sign of doubt or a balanced back and forth in the passage, which is absent. Antagonism would mean pushing back against the trend, but the author instead explains why it matters and treats it as legitimate. Indifference would mean a flat, uninvested description, but the passage spends its final section building up to and explaining this change, which shows the author cares about it and views it favourably.
Since the author's language treats the reform of literary canons by women as a welcome and overdue shift, the best label for that attitude is endorsement, so option 4 is correct.