A hydrocarbon \( C_n H_m \) is burnt in air (O\(_2\) + 3.78N\(_2\)). The stoichiometric fuel to air mass ratio for this process is
Note: Atomic Weight: C(12), H(1) Effective Molecular Weight: Air(28.8)
| Group-I | Group-II | ||
| P | Trilobite | 1 | Periproct |
| Q | Brachiopod | 2 | Hypostome |
| R | Bivalve | 3 | Deltidial plate |
| S | Echinoid | 4 | Lunule |