Q89. Goblet cells of the alimentary canal are modified from

2. Columnar epithelial cells

Some of the columnar or cuboidal cells get specialized for secretion and are called glandular epithelium.
They are mainly of two types:
unicellular, consisting of isolated glandular cells (goblet cells of the alimentary canal), and
multicellular, consisting of a cluster of cells (salivary gland).