💡 Detailed Explanation
The verb '続ける' (to continue/keep up) is read as 'つづける' (tsuduzeru). Note that although it sounds like 'tsuzukeru', due to historical kana usage (historical/systematic spelling from '続く' つづく), it is written in hiragana as 'つづける' with 'づ' (du) rather than 'ず' (zu). Sentence translation: 'Continuing this work is difficult.' '大変' (taihen) means tough or difficult. The other options are incorrect hiragana spelling variations.