The correct answer to the First in a Series of Occasional Linguistics Quizzes is b.
English and Spanish have different phonotactic constraints.
While the /sk/ consonant cluster is perfectly acceptable to English speakers and is not usually even given a second thought, the cluster is not a psychological reality to Spanish speakers. Because Spanish speakers do not recognize the cluster, their phonotactic constraints do not allow the /sk/ cluster to appear in the same syllable. The result is Spanish speakers will insert the vowel /e/ before the cluster which forms another syllable and breaks apart the /sk/cluster.