Final answer:
The correct word to complete the sentence is 'blatant,' which indicates shameless obviousness that aligns with the tone of the statement.
Step-by-step explanation:
The correct word to fill in the blank in the sentence "It seems to me that such ____ hypocrisy is indicative of a thoroughly opportunistic approach to running for office, I said sadly." is blatant. The word blatant means very obvious and intentional, without any attempt to be hidden. Both overt and blatant could technically work in this context since they suggest an openness about the hypocrisy, but blatant carries a stronger connotation of shamelessness which fits with the tone of the sentence. The choices subtle and covert do not fit because they imply secrecy or concealment, which is contrary to the meaning intended in the context provided.