Read the following statements marked as Assertion (A) and Reason (R). Choose the correct option. Assertion (A):Generative Design Software is increasingly used by ISRO for optimizing structure and weight distribution in aerospace components. Reason (R):Generative design tools are specifically developed for modeling cryogenic fuel tanks used in PSLV variants.

Correct — C. The key accepts A: generative design software, which produces many candidate shapes that meet set loads and constraints, is used in aerospace work to cut weight.

R fails on two counts. First, generative design is a general-purpose method, not a tool specifically developed for one component.

Second, PSLV has no cryogenic stage: its four stages are solid, liquid (Vikas), solid, and liquid with two Earth-storable engines. So R is false: option (c).

Why the others are wrong

• (a)
  Both A and R are true, and R is the correct explanation of A — R cannot explain A because R is false. Generative design is not built for cryogenic tanks, and PSLV's four stages use solid propellant or Earth-storable liquids, with no cryogenic stage.
• (b)
  Both A and R are true, but R is not the correct explanation of A — This needs R to be true, and it is not. The cryogenic upper stage flies on GSLV, not PSLV, and generative design is not specific to fuel tanks.
• (d)
  A is false, but R is true — The key treats A as true, so (d) fails at the first step. It also calls R true, which the absence of a cryogenic stage on PSLV rules out.

Generative design is an iterative process in which software generates many design options that satisfy constraints a designer sets, such as loads, materials and weight.

Generative design is also a lightweight-design method for 3D printing (additive manufacturing), which can build the complex shapes it produces.

PSLV, which ISRO calls its workhorse, has four stages: PS1 (S139 solid motor), PS2 (Vikas liquid engine), PS3 (solid) and PS4 (two liquid engines on MMH and MON). GSLV, by contrast, carries a cryogenic upper stage (CUS) as its third stage.

Key facts

• PSLV has four stages: PS1 solid (S139), PS2 liquid (Vikas, UDMH + N₂O₄), PS3 solid, PS4 liquid (two engines, MMH + MON).
• GSLV's third stage is the Cryogenic Upper Stage (CUS).
• PSLV variants CA, DL, QL and XL use 0, 2, 4 and 6 strap-on boosters.
• Generative design software produces many candidate designs that satisfy designer-set constraints such as loads and weight.

Common traps

• Marking R true because cryogenic technology sounds like ISRO's flagship work: PSLV has no cryogenic stage, GSLV does.
• Choosing (b) after deciding R is unrelated to A: (b) still requires R to be true.

No directly related past PYQ was found.