Question 4 a. Show that EQCFG is co-Turing recognizable b. A commuter scientist was asked to help deciding whether two blood samples contain similar or different viruses (A=COVID-19 and B= MERS for example) i.e whether or not they are equivalent. By considering that each virus is a set of strings A* and B* where A and B are the genetic structures (contains letters) for each of them. 1. Is this problem decidable? 2. If so (i.e., if it is decidable), use the decidability theory to design a solution. If not, use the reducibility approach to prove that it is NP