Answer:
a and b
Explanation:b. a socially awkward moment - The interaction between the stranger and the homeowners creates a socially awkward moment as the stranger shows an unusual interest in the basement door, which makes the homeowners uncomfortable.
d. a bizarre interruption of ordinary life - The presence of the stranger and his fixation on the basement door disrupts the ordinary life of the homeowners and introduces an element of the bizarre into the narrative.
These elements contribute to the sense of unease and suspense often associated with the modern Gothic style.