Even after several failed attempts to get the company’s approval for the new proposal, she persisted ________ refining her pitch and was eventually able to convince the board to move forward with her idea.

• শূন্যস্থানে সঠিক উত্তর - in
Sentence: Even after several failed attempts to get the company’s approval for the new proposal, she persisted in refining her pitch and was eventually able to convince the board to move forward with her idea.

• Persist in something/in doing something:
English Meaning - To try to do or continue doing something in a determined but often unreasonable way.
Bangla Meaning - যুক্তি, ব্যর্থতা বা বিরোধিতা সত্ত্বেও কোনো বিষয়ে নিজস্ব অভিমত বজায় রাখা; নাছোড়বান্দার মতো অটল থাকা।

• Example Sentences:
- He persists in crossing the river even in very windy weather.
- If he persists in asking awkward questions, then send him to the boss.

• এছাড়াও,
Persist with:
Meaning - কোনো বিষয়ে বিরতিহীনভাবে পরিশ্রম করে যাওয়া।
Example - The government is persisting with its ambitious public works programme.

Source:
1. Cambridge Dictionary.
2. Accessible Dictionary by Bangla Academy.