Which best corrects the tense shift by the modifying the underline verb swimming ,a had swimming b, swim, c, had swam d, swum

Anja wrote a conclusion that restates her main ideas and thesis. what is the best way for her to fully develop her conclusion? she should add a humorous anecdote to fully engage the reader. she should introduce a new idea that builds on her thesis statement. she should show how her thesis and ideas are connected to one another. she should support her main ideas with strong evidence that explains them.