$A$ student was given a sample of two tissues. He observes the tissues under the microscope and draws their figures ($1$ and $2$) as shown below.

• A
  $1$: Columnar cells bearing cilia; $2$: Unicellular glandular epithelium
• B
  $1$: Cuboidal cells bearing cilia; $2$: Multicellular glandular epithelium
• C
  $1$: Compound cells bearing cilia; $2$: Unicellular glandular epithelium
• D
  $1$: Columnar cells bearing cilia; $2$: Multicellular glandular epithelium