With a BCECE rank of 1787 in the General category and a PCB stream, you have a good chance of securing admission to various government and private colleges in Bihar. Your rank is competitive for courses like B.Sc. in Agriculture, B.Sc. in Nursing, B.Sc. in Biotechnology, or other related programs offered by government institutions. However, the exact availability of seats will depend on the cut-offs for the year and the specific institutions. It's advisable to check the previous years' cut-off trends and participate actively in the counseling process to maximize your chances of admission to a suitable course.