UPSC Civil Services 2018 Prelims General Studies Paper I

ICSE Class 9 textbook Page 150 says Buland Darwaza constructed in red and yellow standstones with white marble inlay in the span of the arches. Other random google books reveal that Khankah too contains white marbles. So, statement #1 ought to be right. Second statement is wrong. "Rumi Darwaza, Bara Imambara, Chhatar Manzil are monuments are fragile in terms of structural strength (because) The common material used for raising most of the monuments in Lucknow was brick and plaster, says Times of India, So, accordingly answer should have been "a" but UPSC has kept 'd' as the official answer.