$5.\backslash ([5+15+5\backslash )$ points$]($a$)$ For the following sequence of MIPS assembly language instructions, calculate the number of data hazards would occur during their executions without stalls in a pipelined implementation. $(5$ points$)$ add r$3$ r$4$ r$2$ sub r$5$ r$3$ r$1$ lw r$6$ r$30$x$45$ or r$7$ r$3$ r$6$ sw r$6$ r$50$x$12($b$)$ Generate an execution time graph to avoid data hazards in the pipelined implementation. $(15$ points$)($c$)$ What is the CPI value for executing these instructions with stalls in their pipelined implementation? $(5$ points$)$