1. A computer program product for generating distractors for text-based multiple choice test (MCT) items, the computer program product comprising: one or more computer-readable storage media and program instructions stored on the one or more computer-readable storage media, the program instructions, when executed by a first computer, cause the first computer to perform a method comprising: receiving, by the first computer from a second computer over a network, in response to information entered into a user interface on the second computer, an MCT item stem and key; submitting, by the first computer, the stem to a Question Answering (QA) system, wherein a QA system is a computer system that, in response to a query, automatically generates a list of candidate answers to the query; in response to submitting the stem to the QA system, receiving, by the first computer, from the QA system a plurality of candidate answers; identifying, by the first computer, one or more incorrect answers in the plurality of candidate answers; extracting, by the first computer, textual features from the stem wherein a textual feature is a term in the stem or a concept semantically related to a term in the stem; applying, by the first computer, a machine learning model to generate a set of semantic criteria associated with the extracted textual features; selecting, by the first computer, as distractors one or more of the incorrect candidate answers that satisfy the generated semantic criteria; creating, by the first computer, an MCT item that includes the stem, the key, and the distractors; and transmitting, by the first computer, the created MCT item via the network to the second computer.