I agree Screening test questions (those pointed out by Sikandarbozdar) were poorly composed but it does not affect in choosing the right answers (If it be let to the common sense).
1. Largest galaxy in universe: a. Andromeda b. Milky-way c. Spiral d horseshoe. (Though the question should have been "the largest spiral galaxy" yet among these four options the largest galaxy is Spiral galaxy
{NGC 6872} so option C is right).
2. Nanga parbat killings: a. 23rd june b. 24th june c. 25th june d. 26th june. (This incident occurred on 22nd june, the news on print media came on 23rd june, {further Wikipedia quoted both dates .. 22nd n 23rd june}, so common sense is required to tick option, the nearest one.)
3. Airship Hindenburg: a. London b. Frankfurt c. New york c. Franc (Though options were wrong, but if you knew the answer you would tick option 'C' cos that accident occurred a place(have a look on the map) between New york n New jersey.)
4. Question number 46, 60 & 76. (Two options are right out of four, if anyone attempted any one of those two, should be given right.)
So your observation is right that the questions were poorly composed; but saying questions were 'invalid' is not justified.