1. Suppose you have a huge database with several millions of records. An error causes a failure whenever the first record of the database is accessed. Discuss how reliable the data-base . base appears to its users. 2. Design an integration. ailing for the module hiereichy of Figure 5A6(b). ' 3. Write a correct version Si the merge algorithm of and then prove it correct. 4. Consider symbolic execution in the general case of an augmented Petri net (with token values, predicates, and actions), where a place can hold more than one token. Explain why path conditions associated with 'firing sequences do not necessarily enable a unique firing sequence and why the same ruing sequence could be enabled by different path conditions.