Chandigarh

I recently cleared all rounds of an interview in a Chandigarh based IT company and the company has verbally agreed on the salary I asked for. However, I'm yet to receive an offer letter. Here's the catch - the HR is asking me to resign from my current job before they'll release the offer letter. I had discussed my 30-day notice period with them earlier, but now they're pushing me to resign ASAP. I'm unsure if this is standard practice or if I should insist on getting the offer letter first. Additionally, my current salary gets credited on the 7th of every month. If I resign now, will my company hold my salary? I'm anxious about making the right move. Should I: A) Resign first and wait for the offer letter B) Insist on getting the offer letter before resigning C) Negotiate a different timeline Please share your thoughts and experiences. Any advice would be greatly appreciated! I have been asked to join within 15-20 days, which is shorter than my notice period. Not sure how to navigate this.