Statements related to human Insulin are given below.
Which statement(s) is / are correct about genetically engineered Insulin?
(a) Pro-hormone insulin contain extra stretch of C-peptide 
(b) A-peptide and B-peptide chains of insulin were produced separately in E.coli, extracted and combined by creating disulphide bond between them.
(c) Insulin used for treating diabetes was extracted from cattle and pigs
(d) Pro-hormone insulin needs to be processed for converting into a mature and functional hormone.
(e) Some patients develop allergic reactions to the foreign insulin.
      Choose the most appropriate answer from the options given below.