Bank nifty will take support at this level of 18950 to bounce back to 19125 and possibly 19200. It is unlikely to break 19400 so calls can be written for these level for coming week expiry. 19700 is another strong resistance unlikely to be broken for a monthly expiry.
On the downside support is seen at 18888, 18700 & 18400. Puts can be written for these levels for weekly/monthly expiry.