Given the task definition and input, reply with output. In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: What type of sound did Dark Heresy convey in it's music given its genre? Passage:Dark Heresy is considered a progressive death metal band. Dark Heresy's 1993 demo Diabolus in Musica was praised for amalgamating "well-chosen sprinklings of classic Morbid Angel with a UK death [metal] flair", and for mixing thrash "with classy chunks of unapologetic metal." Although dismissed by rock music magazine Kerrang! as "a widdly Carcass", their 1995 album Abstract Principles Taken to Their Logical Extremes was praised by extreme music magazine Terrorizer, who wrote that "Dark Heresy's music is not about mind-numbing brutality and dazzling speed, but is about complex and reflective musical structures supporting complex ideas ... while the vocals swing from gruff grunts to choral chants", and described Diabolus In Musica as "one of the most inventive works from an occultist band." Writing in Isten magazine in 1996, Endre Begby described Dark Heresy as "speak[ing] a tonal language very uncommon in death metal" and "break[ing] out of the fifth and major/minor third patterns." He similarly compared part of Abstract Principles Taken to Their Logical Extremes to Morbid Angel's 1989 debut album Altars of Madness, while noting that other parts are "totally flipped out, finding no comparison in modern metal", and summing up that Dark Heresy "fuck with the very foundation of death metal as we know it". Heavy metal and hard rock website Worshipmetal.com agreed with these assessments when revisiting Abstract Principles Taken to Their Logical Extremes in 2017, noting the complex compositions, and adding that Dark Heresy "seemed to throw every single idea into the mix, culminating in a bewildering experience that managed to be both beautiful and brutal in the same breath", and finding similarities between Dark Heresy's music and that of Carcass, Pestilence, and the Mahavishnu Orchestra, and describing their approach to songwriting as "difficult to pin down but ... utterly unique nonetheless."
Links: a. Death metal b. Death metal c. Terrorizer (magazine) d. Kerrang!
a