Which type of engineer develop surgical instruments, such as lasers, and may develop artificial organs and limbs?

The type of engineer described above is the biomedical engineer. These type of engineers typically design biomedical equipment and devices, such as artificial internal organs, replacements for body parts, and machines for diagnosing medical problems.  They install, adjust, maintain, repair, or provide technical support for biomedical equipment.

When you are making a guess you are forming a hypothesis

D.) domain, kingdom, phylum, class, order, family, genus, species