Select the alternative in which the words are spelt correctly.

The correct answer is Option A (courageous, serviceable, perseverance, observatory).

Key Points:
• This question evaluates English spelling accuracy across multiple complex words.
• Option 1 is correct because all four words are spelled perfectly: 'courageous' (keeping the 'e' to maintain the soft 'g' sound), 'serviceable' (also keeping the 'e' for the soft 'c'), 'perseverance' (often misspelled with an 'e' instead of 'a' at the end), and 'observatory'.
• In Option 2, 'beneficient' is misspelled (it should be 'beneficent'). In Option 3, 'planetorium' is incorrect (it should be 'planetarium') and 'catagorical' is wrong (it should be 'categorical'). In Option 4, 'suggestable' is a common misspelling of 'suggestible'.
• MPSC spell-check questions usually target words with tricky suffix rules (like -able/-ible or retaining the silent 'e').
• Key Takeaway: Remember: Words ending in -ce or -ge usually keep the 'e' before suffixes starting with 'a' or 'o' (e.g., courageous, serviceable).